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ii nli editorial coordination and completion by 

CYNTHIA ELLENPORT ROSENBAUM, B.S. 
N G. GHOSHAL, G.V.Sc., D.T.V.M., 

Dr. Med. vet., Ph D, 

DANIEL H1LLMANN. D.V.S., Ph.D. 



Volume 2 


Sisson and Grossman’s 

The Anatomy 
of the 

Domestic Animals 

ROBERT GETTY, D.V.M., Ph.D. 

Late Distinguished Professor and Head, 

Department of Veterinary Anatomy, 

Iowa State University 


fifth edition 



ML SU- CENTRAL LIBRARY 


83274CL 



© W B Saunders Company, 1975 

Copyright 1910, 1914, 1938 and 1953 by WB Saunders Company 

All rights reserved No part of this publication may be reproduced or transmitted, in 

any form or by any means, witthout permission 

First published in India, 1977, by 

THE MACMILLAN COMPANY OF INDIA LIMITED 
Delhi Bombay Calcutta Madras 

Associated companies throughout the world 

SBN 33390 209 1 

Repnnted m India undeT license from V/ B Saunders Company, 

West Washington Square, Philadelphia, Pa 19105, USA 

This edition Is for sale only In India, Pakistan, Bangladesh, 

Nepal Sri Lanka, Burma, Malaysia, Singapore, Hong Kong 
and Indonesia 

Published by S G Wasam for The Macmillan Company of India Ltd 
and printed at Pearl Offset Press, Kirtt Nagar, New Delhi 



CONTRIBUTORS 


DICK M BADOUX, Ph D , Reader in Biomechanics, Anatomisch Instituut, Faculteit der 
Diergeneeskunde, Rijksuniversiteit Utrecht, 141 Bekkerstraat, Utrecht, The Nether- 
lands Biomechanics 

JULIAN J BAUMEL, Ph D , Professor of Anatomy, School of Medicine, Creighton Uni 
versity, Omaha, Nebraska 68178, Chairman, International Committee on Avian 
Anatomical Nomenclature A ves Heart and Blood Vessels and Nervous System 

HORST DIETER DELLMANN, Docteur Veterinaire, Habil(Pli D ), Professor of Veterinary 
Anatomy, College of Veterinary Medicine, University ol Missoun, Columbia 65201 
Co-author, Central Nervous System of all domestic mammals plus General 

LIBERATO, J A DiDIO, M D , D Sc , Ph D , Professor, Department of Anatomy, Medical 
College of Ohio at Toledo 43614 Dean of Graduate Studies, Chairman, Department of 
Anatomy Anatomical Variations and General Splanchnology 

CHARLES DAVID DIESEM, D V M , M Sc , Ph D , Professor of Veterinary Anatomy, 
College of Veterinary Medicine, The Ohio State University, Columbus 43210 Eye of 
all domestic mammals plus General 

CYNTHIA RUTH ELLENPORT (Mrs Irving Rosenbaum), B S , 5308 Adams St , Holly- 
wood, Fla 33021 General Introduction, Urogenital System, Spleen, Ear, Organs of 
Smell and Taste, Porcine Common Integument, Carnivore Digesttve and Urinary 
Systems, Ear, Olfactory Vomeronasal and Gustatory Organs, Editor of book 

M A EMMERSON, D V M , MS, Dr Med Vet (Zurich), Professor Ementus (formerly 
Professor and Head), Department of Obstetrics and Radiology, College of Veterinary 
Medicine, Iowa State University, Ames, Diplomat American College of Veterinary 
Radiology, Home address, 111 Lynn Ave , Ames, Iowa 50010 Anatomy in Radiology 

ALAN FEDUCCIA, Ph D , Associate Professor, Department of Zoology University of N 
Carolina, Chapel Hill 27514 Aves Osteology 

SHAM S GANDHI, B V Sc and AH, MS, Ph D , Assistant Professor, Department of 
Pharmacology, St Louis University School of Medicine, St Louis, Missoun 63104 Ear 
of Ruminant and Porcine 


ROBERT GETTY, Dy M , MS, PhD, Late Distinguished Professor and Head Depart- 
mem of Veterinary Anatomy, Iowa State University, Ames General Osteology, 
Syndesmology, Heart and Blood Vessels, Lymphatics, Nervous Sijstem Eauiiie 
Osteology (except skull), Ruminant Myology, co authored Lymphatic Sustnm* nf 
all mammals (except goat) and Cranial Nerves of all mammals directed M S and 
Ph D research in the areas of the peripheral and autonomic nervous system arterial 
supply to various parts of the body and the lymphatic system ^ ’ 

NANI G GHOSHAL, G V Sc , D T V M , Dr Med vet , Ph D Pm 

Anatomy, Department of Veterinary Anatomy, Pharmacology .mtl pk \ Veterinary 
of Veterinary Medicine. Iowa State Univeri ty ! aScs 5001^ „ h> 7 C ° llege 
(except Brain), Spinal Nerves and Abdominal and Cm,,, ! » , r ‘ a ” d * r 'f, r ‘f s 
ntesltc mammals, coauthor. Lymphatic System of Gof, rrTfTr ° f *5 
Ruminant Myology (except head), reviewed Ostpnlnnf, r 0t ’ T f vts f i * Egume and 
mammafs, acted in the capacity of consultant nn head) of all domestic 

ticularly in the areas of nomenclature German * ^ a,s P ects °f the text, par- 

references ’ ° erman translations and bibliographical 


v 



VI 


CONTRIBUTORS 


HUGO P GODINHO DVM MS, PhD Associate Professor of Vctcrinir> Amtomy 
Unnersidade Federal de Minas Gerais Instituto de Citnclas Biologicas Bclo Horizonte 
M G Brasil Co-author Cranial Nenes of all domestic mammals 


ROBERT E HABEL DVM MSc.MVD Professor of Anatomy, and Head of Depart 
ment New York State College of Veterinary Medicine, Cornell Univcrsit) Ithaca 
14853 Ruminant Introduction Digesthe System Pehlc Diaphragm and Branches 
of Abdominal Aorta to Digestne Organs reviciicd General Digesltie System and 
portion of General Splanchnology 


WILLIAM CURRIE DOUGLAS HARE M A (lie) B Sc PhD DVM & S MRCYS. 
formerly Professor of Anatomy and Head of Laboratories of Anatom) School of Yet 
ennary Medicine and Graduate School of Arts and Sciences University of Penns) 1 
vania Philadelphia currently, Research Scientistand Head, Diseascsof Cattle Section ' 
Animal Diseases Research Institute, Animal Pathology Division, Health of Animals 
Branch Canada Department of Agriculture. 801 Fallowfidd Rd , Ottawa, Ont K21I 
8P9 General Paranasal Sinuses . and Respiratory System Respiratory System of 
all domestic mammals and Radiographic Osteology Illustrations ofCarnharc 


JOHN B HERRICK, B S.DV MM S , Professor and Extension Veterinarian. Cooperativ e 
Extension Service Kildee Hall, Iowa State University, Ames 50010 Preface and 
Bio«;r»pf«icri( SI etch of Dr Robert Cetly J 


DA EH"r,^ 

< Avun Anatomical ^ome^cbtu^^ Ale on 
Silttcm end Lymphatic S„u," J "T. Uro »" ,l ” ! 

drew many of the original illn.lroltoM in' II icAim ™,,,™ ’ l,r ‘ rn ' rrl " 

liauSSJu 1 «Sra»°FoSSMH Scl ' nc '- 

of Vetcm^Afcdlcino^UmvS ’Z °h V “' ri " ar >' Anatomy, Collcsc 

JOHN SCOTT McKIBBEN.B S.DV M M S Ph ra r> r 

JOHN McLELLAND, B VJll S MVin D . . 

co author. Ate. Ceiomtc "»■* CiKSJ&Ell. 

B S NANDA, B V Sc and AH Ph n 

Histology, College of Veterinary n ° r , an<J Head of V «erinarv Anatnm. j 

Punjab, India Bloods^ t0 Br 0 , Lud££ 

WAYNE H RISER DVM Ms Dr M~» 

fessor, School of Veterinary Medicine nXT* ’ *1 A (f!on )• Research Assistant o 
Affiliate Staff Alfred I duPont In*toASa^S?2f nn9 »|'« n *a Philadelphia” 9 fw* 
Carniiore Introduction nd Consultant Army Bio Sensor Research’ 

JAMES R ROONEY. A B , D V M . M S p m f 

Center. School of Veterinary Medicine'. Univ^w f rX etennar >' p a<hologv N en 

Equine Introduction ml,,,of P '"’'*Vl>an,a.|.h ll " dc |" l '" 



CONTRIBUTORS 


vi i 

LAM BIT I SAAR, Dr Med vet , Associate Professor of Veterinary Anatomy, University of 
Guelph, Ontano Veterinary College and Veterinarian, Canada Department of Agri- 
culture, Health of Animals Branch, home address, 4020— 40th Ave , N W , Calgary, 
Alberta, Canada Co-author, Lymphatic System of all domestic mammals (except 
goat) including General Lymphatic System 

LORENZ E ST CLAIR, D V M , M S , Ph D , Professor of Anatomy, College of Veterinary 
Medicine, University of Illinois, Urbana 61801 Genei al Myology and Teeth Teeth oj 
all domestic mammals and Canuvoie Myology 

S SISSON flW of booh not attributable to other authors 

WILLIAM P SWITZER, D V M , M S , Ph D , Associate Dean for Research and Professor of 
Veterinary Microbiology and Preventive Medicine, Iowa State University, College of 
Veterinary Medicine, Ames 50010 Porcine Intioduction 

KUSMAT TANUDIMADJA, DVM, MS, PhD, Senior Lecturer, Veterinary Anatomy 
Division Department of Zoology, Faculty of Veterinary Medicine, Bogor Agricultural 
Umversity (I P B ) Bogor, Indonesia Co author, Lymphatic System of Goat 

JAMES C VANDEN BERGE, Ph D , Assistant Professor of Anatomy, Indiana University 
School of Medicine, Northwest Regional Center for Medical Education, Gary 48823* 
Ates Myology 

WALTER GEORGE VENZKE, DVM.MS ,PhJ) , Prpfessorand Chairman, Department of 
Vetennan Anatomy Assistant Dean and Secretary, College of Veterinary Medicine The „ 
Ohio State University, 1900 Coffey Rd , Columbus 43210 Endocrinology 6f all do . , 
mestic species including the Thymus of all domestic mgmmals plus general 
comments 

C J G VVENSING, D V M , Ph D , Reader in Veterinary Aftatomy and Embryology, Ana 
tomlsch Instituut, Faculteit der Diergeneeskunde, Rijksunn ersiteit Utrecht, 141 
Bekkerstraat, Utrecht, The Netherlands General Celomic Cavities and Serous 
Membranes, and General Descent of Testicles 

SHEILA SINCLAIR WHITE, BVMS, PhD, DA, MRCVS, Lecturer in Anatomy 
University of Glasgow, Scotland Aves Larynx 



EDITOR’S 

FOREWORD 


In 1958, when Dr Getty signed the contract with Dr Grossman and Saunders 
to revise the Fourth Edition of Sisson and Grossman’s Anatomy of the Domestic 
Animals, he envisioned a complete Anatomy of each of the domestic mammals 
(horse, ox, sheep, goat, pig, dog and cat) and the domestic birds He wanted the 
matenal for each species to stand on its own, unlike most other anatomy texts, 
which were basically comparative Since previous editions of Sisson and Gross 
man concentrated primarily on the horse, with mainly only the salient differences 
of the other species noted, this meant more work than was physically possible for 
one individual Therefore, Dr Getty also envisioned an authoritative presentation 
which would utilize the expertise of many of the prominent world authorities 
In addition, in 1957, the first meeting of the International Association of 
Veterinary Anatomists appointed an International Committee on Veterinary 
Anatomical Nomenclature (I C V A N ), which consisted of, among others, Drs 
Getty, Habel and Venzke Thus, Dr Getty also envisioned the Fifth Edition of 
Sisson and Grossman as encompassing the new accepted international nomen 
clature 


Complete, detailed information was lacking in the literature on most of the 
domestic species, except the horse (an anatomy of the dog was then in progress 
by Dr M E Miller) After recruiting several authorities who would be responsi 
ble for writing various portions of the text. Dr Getty encouraged his graduate 
students, and colleagues who were interested in gross anatomy, to concentrate 
on the areas of the peripheral and autonomic nervous systems, the arterial supply 
to various parts of the body, and the lymphatic system Thus, most of the ma 
tenal m this edition is based on original research 


Dr Getty also realized the importance of good illustrations as an adjunct to 
textual matenal, especially m a discipline such as anatomy They are particularly 
important today because time is a cntical problem in most veterinary schools 
around the world, and because of the considerable mass of information which 
must be imparted to the student in an area as basic as anatomy Thus we h ve 
retained about 670 illustrations from the previous editions and have added over 
1000 new illustrations Bibliographies from the world literature have been added 
to all chapters A zoological classification for each species is al«?n wi, a 
When Dr Getty died early m 1971, the major portion of r , 
organized, and in vanous draft stages However, it was necessarv * 5 °° k w3S 
contributors to handle areas such as the avian portfaTwhSh Dr 
planned to wnte himself In addition, the first edition of the into « Getty 
clature ( Nomina Anatomtca Veterinaria [N A V 11 had Ro~„ national nomen 
and the second edition was to be finalized at a meettnc m , Polished in 19 &B 
and published in 1973 The nomenclature on the avian he SUmmer 
formalized, except in very preliminary drafts In order in P6Cles not T et bee ^ 
the new nomenclature as possible, and to finally* »r ° inCOrporate as 1111,011 0 

Ze those Portions not yet con** 


IX 



PREFACE TO 
THE FIFTH EDITION 


Anatomy is not a dead subject ft is a living part of constant scientific re* 
search It is also the foundation for all biological knowledge 

This revised edition of Sisson and Grossman's Anatomy oF the Domestic 
Animals was spearheaded by the late Dr Robert Getty who passed away on 
February 18, 1971 At the time of his death, most of the text was finished and 
99 per cent of the illustrations were complete 

Dr Robert Getty, while revising this text, served as Chairman of the Section 
on “Organa Sensuum” of the International Committee on Veterinary Anatomical 
Nomenclature of the World Association of Veterinary Anatomists Through this 
committee a defined, authoritative anatomical nomenclature was formulated and 
published Their efforts have been incorporated in this text 

The Fifth Edition of the text presents a new format, in which each species is 
considered as a separate entity The first four editions considered the horse as the 
basic animal and described the other species in a comparative manner In this 
edition the material -both illustrative and textual— for the other species has been 
greatly expanded The new format was introduced so that the text would be more 
useful to students around the world In this format the student can concentrate 
on a specific species since all of us systems aie included in one section It was 
one of Dr Getty’s basic tenets that jf we arc to know physiologic and pathologic 
changes w e must Know the normal This philosophy is relayed to the student and 
reinforces the fact that “Anatomy” is a living subject 

A revision of this magnitude cannot be accomplished by one person alone 
Graduate students of Dr Getty, through their theses, contributed to this revision 
as dul many renowned anatomists the world over 

Miss Cynthia R Ellenport, Dr Daniel J Hillmann and Dr Nam G Ghoshal 
contributed greatly to the text and completed the revision after Dr Getty’s death 
Dedicated to Dr Robert Getty, and to the many others who have contributed 
to the know ledge of the anatomy of domestic animals, and consequently, to man’s 
welfare, this revised edition is further evidence of a scientific standard of ex* 
cellcnce 


John B Heiuuck 



CONTENTS 


Note- The lower case Greek phi (<fr) following certain entries indicates that these are not 
official terms as published in the Nomina Anatomica Veterinaria in 1973. 


VOLUME 1 

GENERAL 

Chapter I 

INTRODUCTION 

C. R. Ellenport 

Anatomy in Radiology 

M. A. E turner son 

Anatomical Variation 

L. J. A . DiDio 

Chapter 2 

^OSTEOLOGY 

R. Getty (Paranasal Sinuses by \V. C. D. Hare) 

Chapter 3 

SYNDESMOLOGY 

/?. Getty 

Chapter 4 

MYOLOGY 

L. E. St. Clair 

Chapter 5 

BIOMECHANICS 

D. M. Badoux 

Chapter 6 

SPLANCHNOLOGY 

L.J.A. DiDio 

Celomic Cavities and Serous Membranes.... 
C.J. G.Wen'tinx 


3 

6 

15 


19 


34 


39 


48 


84 

87 


General . 
S. Sisson 


98 



Xiv 


CONTENTS 


Chapter 7 

DIGESTIVE SYSTEM 

S Sisson ( Teeth b} L E Si C\atr\ 

101 

Chapter $ 

respiratory system 

W C D Hare 

113 

Chapter 9 

UROGENITAL SYSTEM 

C fl Ellenport 

145 

Chapter 10 

ENDOCRINOLOGY 

W G VeniAe 

150 

Chapter 1 1 

HEART AND BLOOD VESSELS 

R Gen > 

104 

Chapter 12 

LYMPHATIC SYSTEM 

L / Saar and k Geti\ 

17G 

Spleen 

C R El Import 

180 

Thymus 

W G Venzke 

181 

Chapter 13 

NERVOUS SYSTEM 

R Getty 

182 

Central 

// D Dellmann and R C Mi Clare 

202 

Chapter 1 4 

SENSE ORGANS AND COMMON INTEGUMENT 


Organ of Vision 

C Diesem 

226 

Ear 

C R Ellenport 

244 

Organ of Smell 

C R Ellenport 

246 

Organ of Taste 

C R Ellenport 

246 



CONTENTS 


XV 


Common Integument 
5 Sisson 


247 


EQUINE 

INTRODUCTION 
J R Rooney 


Chapter 15 
OSTEOLOGY 

^ R Getl\ (Skull by D J Htllmann) 


Chapter 16 
SYNDESMOLOGY 
S Sisson 

Chapter 17 
MYOLOGY 

5 Sisson 

Chapter 18 

DIGESTIVE SYSTEM 

5 Sisson (Teeth by L E St Chur) 

Chapter 19 

RESPIRATORY SYSTEM 
W C D Hare 

Chapter 20 

UROGENITAL SYSTEM 
V Sisson 

Unnary Organs 

Male Genitalia 

Female Genitalia 

Chapter 21 

ENDOCRINOLOGY 
W G Venzke 

Chapter 22 

HEART AND ARTERIES 

N G Ghoshut (Blood Supply to Brain by B S Nunda) 


524 

531 

542 

550 

554 



XVI 


CONTENTS 


Chapter 23 

lymphatic system 

L l Saar and R Geliy 

Spleen 
S Sisson 

Thymus 
W G Venzke 

Chapter 24 

NERVOUS SYSTEM 
Central 

H D DeUmann and R C McClure 

Peripheral 

Cranial Ner\es 
H P Godtnha and R Geliy 

Spinal Nerves 
N G Ghoshal 

Autonomies 

J S McKibben and N G Ghoshal 
Chapter 25 

SENSE ORGANS AND COMMON INTEGUMENT 

Organ of Vision 
C Dtesem 

Ear 

S Sisson 

Organ of Smell 
S Sisson 

Organ of Taste 
S Sisson 

Common Integument 
S Sisson 


619 

G30 

630 


G33 

G50 

GG5 

688 

703 

719 

728 

728 

728 


RUMINANT 

INTRODUCTION 

R E Habel 739 

Chapter 26 
OSTEOLOGY 
S Sirson 


741 



CONTENTS 


xvii 


Chapter 27 



5. Sisson 

Chapter 28 

MYOLOGY 

R. Getty ( Bar by S. S . Gandhi and Pehic Diaphragm by R. E. Habel) 

Chapter 29 

DIGESTIVE SYSTEM 

R. E. Habel (Teeth by L. E. St. Clair) 


Chapter 30 

RESPIRATORY SYSTEM. 
W. C. D. Hare 


Chapter 31 

UROGENITAL SYSTEM 
S. Sisson 

Urinary Organs 937 

Male Genitalia • 939 

Female Genitalia - 946 

Chapter 32 

ENDOCRINOLOGY 955 

W. G. Venzke 

Chapter 33 

HEART AND ARTERIES 960 

N . G. Ghoshal ( Blood Supply to Brain by B. S . Nanda; Branches 
of Abdominal Aorta by R. E. Habel) 

Chapter 34 

LYMPHATIC SYSTEM 



L. 1. Saar and R. Getty 


Ovine 


L. 1. Saar and R. Getty 


Caprine 


K. Tanudimadja and N. G. Ghoshal 

t 

Spleen 

S. Sisson 


Thymus * 

W. G. Venzke 

.. 3064 



XV111 


covn NTS 


Chapter 35 


NERVOUS SYSTEM 

Central 

H D Delhnann and R G McClure 

10G5 

Peripheral 


Cranial nerves 


Bovine 

H P Godinho and It Geliy 

1081 

Ovine 

H P Godinho and R Cell) 

1094 

Caprine 

H P Godinho and R Getty 

1108 

Spinal nerves 

N G Clioshd 

1124 

Autonomies 

J S McKibben and N G Ghoshal 

1151 

Chapter 36 

SENSE ORGANS AND COMMON INTEGUMENT 


Organ of Vision 

C Diesem 

1180 

Ear 

S Sisson and S S Gandhi 

1204 

Common Integument 

S Sisson 

1208 

Organ of Smell 

S Sisson 

1211 

Organ of Taste 

5 Sisson 

1211 

INDEX 

i 

VOLUME 2 


PORCINE 


INTRODUCTION 

W P Switzer 

1215 

Chapter 37 

OSTEOLOGY 

S Sisson and D J HtUmann 

1216 



CONTENTS 


XIX 


Chapter 38 
SYNDESMOLOGY 
5 Sisson 

Chapter 39 
MYOLOGY 

S Sisson (Ear by S S Gandhi) 

Chapter 40 

DIGESTIVE SYSTEM 

S Sisson (Teeth by L E St Clair) 

Ch ipter 4 1 

RESPIRATORY SYSTEM 
W C D Hare 

Chapter 42 

UROGENITAL SYSTEM 
5 Sisson 

Unnary Organs 

Male Genitalia 

Female Genitalia 

Chapter 43 

ENDOCRINOLOGY 
W G Venzke 

Ch ipter 44 

HEART AND ARTERIES 

N G Ghoshal (Blood Supply to Brain by B S Nando) 

Chapter 45 

LYMPHATIC SYSTEM 

L / Saar and R Getty 

Spleen 
S Sisson 

Thymus 
n G Venzke 

Chapter 46 

NERVOUS SYSTEM 
Central 

If D Dellmann and R C McClure 


1253 

1256 

1268 

1283 

1297 

1299 

1301 

1304 

1306 

1343 

1358 

1359 

1360 



CONTENTS 


Peripheral 


Cranial Nerves 

H P Godmho and R Getty 

1370 

Spmal Nerves 

N G Ghoshat 

1383 

Autonomies 

J S McKibben and N G Ghoshal 

1397 

Chapter 47 

SENSE ORGANS AND COMMON INTEGUMENT 


Organ of Vision 

C D Diesem 

1409 

Ear 

5 S Gandhi 

1418 

Common Integument 

C R Eilenport 

1420 

Organ of Smell 

S Sisson 

1422 

CARNIVORE 


INTRODUCTION 

1425 

W H Riser 

Chapter 48 

OSTEOLOGY 


Canine 

S Sisson 

1427 

Feline Atlas 

1483 

Chapter 49 

SYNDESMOLOGY 


5 Suson 

1504 

Chapter 50 

MYOLOGY 


L E Sr Clair 


Dog 

1507 

Cat 

1534 

Chapter St 

DIGESTIVE SYSTEM 


C R EUenport ( Teeth by L E St C lair) 

1538 



CONTENTS 


XXI 


Chapter 52 

1559 

RESPIRATORY SYSTEM 

W. C.D. Hare 

Chapter 53 

UROGENITAL SYSTEM 
C. R. EUenport 

Urinary Organs * 576 

Male Genitalia 3580 

Female Genitalia 

Chapter 54 

ENDOCRINOLOGY 1590 

W. G. Venzke * 

Chapter 55 

HEART AND ARTERIES 1594 

N.G. Ghoshal (Blood Supply to Brain by B. S. Nando ) 

Chapter 56 

LYMPHATIC SYSTEM 

L. I. Saar and R. Getty 

Canine .1652 

Feline 1661 

Spleen 1669 

5. Sisson 

Thymus 1670 

W. G. Venzke 

Chapter 57 

NERVOUS SYSTEM 

Central j671 

//. D, Dellmann and R. C. McClure 

Peripheral 

Cranial Nerves 1686 

//. P. Godinha and R. Getty 

Spinal Nerves ^ ^ jG99 

N.C.Chmhof 

Autonomies j723 

J. S. McKlbben and N. G. Ghoshal 



xxn 


CONTENTS 


Chapter 58 

SENSE ORGANS AND COMMON INTEGUMENT 


Organ of Vision 

C Dtesem 

1741 

Ear 

C R Ellenporl 

1769 

Olfactory and Vomeronasal Organs 

C R Ellenporl 

1780 

Gustatory Organ 

C R Ellenporl 

1781 

Common Integument 

S Sisson 

1782 

AVES 

Chapter 59 

INTRODUCTION 

A S King 

1787 

Chapter 60 

OSTEOLOGY 

A Feduccta 

1790 

Chapter 61 

MYOLOGY 

J C Van den Berge 

1802 

Chapter 62 

CELOMIC CAVITIES AND MESENTERIES 

J McLelland and A S King 

1849 

Chapter 63 

DIGESTIVE SYSTEM 

J McLelland 

1857 

Chapter 64 

RESPIRATORY SYSTEM 

* S Km s (Urym b, s S While) 

Chapter 65 

UROGENITAL SYSTEM 

A S King 

1883 

Urinary Organs 


Male Genitalia. 

1919 


1927 



CONTENTS 

XXI 11 

.... 1935 

Female Genitalia 

.. 1959 



Chapter 66 

ENDOCRINOLOGY 

W . G. Venzke 

... 1965 

Chapter 67 

HEART AND BLOOD VESSELS 

J. J. Bourne! 

.. 1968 

1969 

Arteries 

... 1981 



Chapter 68 

.... 2010 

LYMPHATIC SYSTEM 

A. S. King 


Chapter 69 

NERVOUS SYSTEM 

J. J. Baum cl 

2019 

Peripheral 

.... 2024 

Cranial Nerves 

2038 

Spinal Nerves 

2053 

Autonomic 

Chapter 70 irMT 

' SENSE ORGANS AND COMMON INTEGU 

2063 

J. McLettand 

2066 

J. McLettand 

2069 

J. McLettand 

.... 2069 

J. Met jrt land 

... 2071 

A . St. Lucas 

1 



PORCINE 


Class 

Subclass 

Infraclass 

Order 

Suborder 

Family 

Genus 

Species 

Subspecies 


Mammalia 

Theria 

Eutheria 

Artiodactyla 

Suina 

Sutdae 

Sus 

scrofa 

domesticut 


1214 



PORCINE - INTRODUCTION 

by W. P. Switzer 


Detailed information on porcine anatomy is becoming increasingly important 
Several factors are interacting to produce this accelerated need Changes in 
commercial production of swine to increasingly specialized swine operations, 
involving large numbers of swine housed in confinement, require the services of 
veterinarians highly skilled m swine practice In addition, progressive purebred 
swine producers are utilizing an ever increasing level of applied anatomy in 
their breeding stock selection 

The many similarities in physiology and gross and microscopic anatomy 
between swine and humans have resulted in the widespread use of swine in 
medical and biomedical training and research The current indications are that 
the pig is the best suited of any of the domesticated animals for such purposes 

Increased research into the various swine diseases, nutrition, housing, 
reproduction and production of a highly desirable pork product— all require an 
increased amount of detailed knowledge of gross and microscopic anatomy, 
embryology and physiology of the normal pig It is a pleasure to observe the field 
of veterinary anatomy responding to these increased demands for more detailed 
information by devoting a section of the ANATOMY OF THE DOMESTIC 
ANIMALS exclusively to swine 


1215 



CHAPTER 


PORCINE 

OSTEOLOGY 


VERTEBRAl COLUMN 

by S. Sisson* 


The vertebral formula is C I T, t .,iLs- 7 S 1 Ca 1 ».M 
(Fig 37-1) 

The Cervical Vertebrae 

(Figs 37-2, 3 and 4) 

The cervical vertebrae are short and wide 
The bodies are elliptical In cross-section, the 


long diameter being transverse. The crania! 
articular surfaces are slightly convex from 
side to side and concave dorsoventrally; the 
caudal ones are slightly concave. A ventral 
crest is not present The arches are wide trans- 
versely, but the laminae are narrow, so that a 
considerable interval ( spatium interarcuale ) 


'Edited by C R-EUenport and reviewed by N G Choshal. 



a. Cranium, b iruxdia c, mandible d, supraspinous fossa, d , infra spinous fossa, e, humerus f p. 
carpus. M * .metacarpus kk •.proximal phalanges 11 . middle phalanges m-m ',’dista! ohalanees r. „ ..u™,,,. 

ilium, q Uchium, t pubis, *, femur, t. patella, u. tibia, v, fibula, w, tarsus. 1H, 7H, first andsevrntb cervical vertebrae, 
K sacrum. 1L. CL. first and sixth lumbar vertebrae. 1R, 14R, firs land last ribs. R,kn..costalcamlag« 1K.W 13 ILw first 

,nd tblnra* v.n.bn, S. ntat. s ^- «f mpula, of ,„ p „Li, 3. ).,ad of 

humerus 4 tubercles of humerus 5 deltoid tuberosity 6. lateral epicondyle of humerus 7, olecranon 8 coxal tubeT 
9 sacral tuber. 10 ischiatic spine, II. Ischiatic tuber, 12. acetabulum. 13, greater wdwwn 
15 lateral epicondyle. 16. cranial border of ubia 17, lateral condyle of tibia, 16-25, carpal bon« 2fC 3 l tarS bwes 
26 , calcaneal tuber. 32-44 can best be seen cm Figure 37-42. (After Eilenbox« s looai ’ ‘ ' 

me 



37- PORCINE OSTEOLOGY 


1217 


5—- i^\ 



G 

FIGURE 37-2. Fourth cervical vertebra of pig; 
lateral view. 

1, cratual and 1 .caudal ends of body, 2 , arch, 3, foramen 
of arch, 4. cranial articular process, 5, spinous process 
6, ventral branch of transverse process 



FIGURE 37-3. Sixth cervical vertebra of pig; cra- 
nial view. 

1, Body, 2, transverse process, 3, transverse foramen 4, 
accessory transverse foramen, 5. articular process, 6 arch. 
7, spinous process 



FIGURE 37-4 Seventh cervical vertebra of pig; 
lateral view. 

1 (number on bone), foramina of arch, 1, cranial and 1', 
caudal ends of body, 2, capitular facet for first rib, 3, arch, 
4, transverse process, 5, 5', articular processes, 6, spinous 
process 


10 cm in the adult), the absence of the ventral 
plate of the transverse process, and the flat- 
ness of the body, which bears a pair of small 
facets on its caudal margin for the heads of 
the first nbs. It has transverse foramina and, 
usually, two foramina in each side of the arch. 


ATLAS 

(Figs 37-5 and 6) 

The dorsal tubercle of the atlas is large The 
ventral tubercle is long, compressed laterally 
and projects back under the axis The trans- 
verse process (wing) is flattened and bears a 
caudal tuberosity. The transverse foramen 


separates adjacent arches dorsally. The pedi- 
cles are perforated by a lateral vertebral fora- 
men in addition to the usual intervertebral 
foramina. The transverse processes divide in- 
to two branches, both of which increase in size 
from the third to the sixth The dorsal branch 
projects laterad and caudad, it is short and 
is thickened at its free end The other branch 
is a quadrilateral plate directed ventrally; each 
overlaps the succeeding one to a small extent, 
and the senes forms the lateral boundary of a 
deep and wide ventral groove. The spinous 
processes (spines) increase In height from the 
third to the last; the cranial ones are inclined 
caudal]), the caudal ones cranially. The last 
cervical vertebra is recognized by the great 
length of its spinous process (approximately 


2 1 




4 5 0 7 

FIGURE 37-5. Atlas of pig. dorsal view. 


1. DorviJ tubercle 2. alar foramen, 3. wins 4. lateral 
-ertrbral foramen 5, dorsal arch 6. ventral tubercle 
• . fovea for d is 



J218 


I ORCINE 



passes through the caudal border of the wing 
to the fossa under the latter and is not visible 
dorsally it is sometimes very small or absent 
The sides of the vertebral foramen bear two 
lateral projections which partially divide it in 
to a ventral narrow part which receives the 
dens and a dorsal larger part ior the spinal 
cord In the fresh state the division is com 
pleted by the transverse atlantal ligament 
which is attached to the projections 


FIGURE 37 8 \xn Of pig cranial view 
1 Dens 2 cranial and 2 caudal articular processes 3 
transverse foramen 4 arch 5 spinous process 

constricted xn the middle and without ventral 
crests Their extremities are elliptical de 
pressed in the middle and prominent at the 
periphery The arch is perforated by a foramen 


AXIS 

(Figs 37-7 and 8) 

The axis has a large spinous process which 
is directed dorsad and caudad The dens is 
a thick cylindrical rod The transverse process 
is very small and the transverse foramen is 
often incomplete 


Thoracic Vertebrae 

(Fig. 37 9) 

The thoracic vertebrae are commonly 14 or 
15 in number Their bodies are relativ ely long 



HCLRE 3 —7 Axis of p g lateral view 

I Dens 2 cranial and 2 caudal an cular ptocessev 3 
caudal end of bod) 4 transverse process 5 Iran* erse 
foramen C arch 7 *p nous process A rows indicate lac 
era I venebral foramen 



vJ Umb rV ,roundbon « 1 ennial and 1 caudal end* of 
7°? ” “ facets for heads of nbs 3 3 articular pro- 
s' 5 ’*' 4 fa f et for head of rib 5 spinous process 
lumbers on bones 1 1 foramina of arches 2 2 trans- 
verse processes 3 3 facets for tubercle* of Tibs 



37— PORCINE OSTEOLOGY 


1219 


FIGURE 37-10. Fourth lumbar 
vertebra of pig; cranial vlenr. 

1, Body, 2, transverse process; 3, 
cranial articular process, 4, mamil- 
lary process, 5, caudal articular 
process; 6, spinous process 



on each side and in most of the senes there is 
also a lateral vertebral foramen in the caudal 
part of the root of the transverse process which 
communicates with the former or with the 
caudal intervertebral foramen. Sometimes 
there is a foramen in the craiiial part of the 
process also. There are mamillary processes 
except on the first two; in the caudal five or 
six vertebrae they project from the cranial 
articular processes The facet for the tubercle 
of the rib is absent or fused with that for the 
head in the last five or six. The last transverse 
process is lumbar in character, plate-like and 
about 2 cm long. Small accessory processes oc- 
cur in the caudal part of the region. The first 
spinous process is broad, very high and in- 
clined a little cramad. The others diminish 
very gradually in length to the tenth, beyond 
which they are about equal The second to the 
ninth are inclined caudad, the tenth is the 
"diaphragmatic” and the eleventh is vertical 
(anticlinal); the rest incline cramad The 
width decreases decidedly from the fourth to 
the tenth, beyond which there is a gradual in- 
crease. The summits are slightly enlarged and 
lie almost in a straight line. 


Lumbar Vertebrae 

(Fig. 37-10) 

The lumbar \ertebrae are six or seven in 
number. The bodies are longer than in the 
thoracic region and bear a ventral crest. They 
become wider and flatter in the caudal part of 
the series. The arches are deeply notched and 
are separated by an increasing space dorsally. 
The mamillary "processes project laterad and 
caudad. The transverse processes are bent 
ventrad and incline a little craniad. Their 
length increases to the fifth and is much di- 
minished in the last.They form no articulation 
with each other or with the sacrum The cau- 
dal edge of the root of the process is marked by 
a notch in the cranial part of the senes, a fora- 
men in the caudal part. The spines are broad 


and incline craniad, with the exception of the 
last, which is narrow and vertical. 

Sacrum 

(Figs 37-11 and 12) 

The sacrum consists usually of four verte- 
brae (Barone, 1966, says sometimes five) 



FIGURE 37-11^ Sacrum and first caudal vertebra 
of pig; dorsal >iew. 


1 l\. Arches of sacral vertebrae, 1. 2, 3. dorsal sacral 
foramina 4. similar foramen between sacrum and first 
caudal vertebra, A. body of first sacral vertebra, B cranial 
articular process, C, win*. D. auricular surface. E. caudal 
articular processes. F. first caudal vertebra. 


1220 


PORCINE 



central >iew CaU ° al ' Cr * lf ' > 

foramina 4 wmlur TonmSi'hl * 2 3 ven,ral «aci 
caudal vertebra A “ crurn and fii 

articuhr proc « 8 C win, D a ^nr al , Verlebra B cra * 

caudal vertebra. g D uncular *urface E fii 


SSL?"- 

are little developed and 6 8p,no “ 8 P r °cesi 
pan Tlie middteof ?he Hm”"!' 01 ’ 1 ? absem 

taned and smoo'h and nre, . SUrface 15 " 
the sacral canal between ad, " 1S openln S s n 
cither side are the dorsal arch cs i 

tubercles which 

processes The nines resemM {i' 5od ar,,cu 
The cranial artieufi omeT ' lhose the , 
The pelvic surface risen,!? 65 ? re very lar| 
hut is not so strangle cTn cd i °l ,lre « 
verse lines are very *stact d d ‘ be ,raI 


Caudal Vertebrae 

dally charactemed^byfbe'pres 1 ” 11 ' are spe 

tional articular processes on the Bra, 0 ? fU " C 
five beyond which these processefll or 
non articular and smaller The oral, b "i. ome 
first five or six are complete TjJ , b ° f Ihe 
processes are broad and plate hke talh''"* 


nnl part of the senes and diminish \ cry’ grad 
ually Not rarely the first caudal tertebra 
unites with the sacrum 


VERTEBRAL CURVES 

The cervical region is practically straight 
The thoracic and lur ibar regions form a gentle 
curse concave centrally, the highest point of 
which is at the junction of the two regions 
the sacnl promontory is not so pronounccdas 
in the ox and the sacral curve is flatter 
Lexer,, The regional lengths of the ver 
tebra column of a large Berkshire soss were 
as follows Cervical 24 cm thoracic, 53 5 cm 
lumbar, 31 cm sacral, 17 cm caudal 35 cm 

recorded reduclion lo 131s very rare c.” JT" 17h ?* b ® cn 

i?,' mmb " 

several observer? Lesbre (1M7? 1 ° * u® r ® cord * ° r 

frequently found 23 ' ‘tales that he has most 




37 -PORCINE OSTEOLOGY 


1221 



6 


FIGURE 37-14. First rib of pig; lateral view. 

1. Head, 2, neck, 3, tubercle, 4, cranial border, 5, vascu 
lar impression; G, ventral extremity 

Ribs 

(Figs. 37-13 and 14) 

The ribs number 14 or 15 pairs, of which 
seven are usually true or sternal and seven or 
eight false or asternal. They are, in general, 
strongly curved m the improved breeds, so 
that there is a fairly distinct angle, except 
toward the end of the series. The caudal 
slope of the caudal'ribs is slight. The first nb 
is prismatic and has a large ventral end and a 
very short cartilage. The width is greatest in 
the third to the sixth, and the length usually 
in the sixth and seventh. The tubercle fuses 
with the head on the last five or six. The 
second to the fifth form synovial joints with 
their cartilages, which are wide and plate-like. 

The fifteenth rib, when present, may he fully developed 
and its cartilage enter into the formation of the costal 
arch; but in most cases it is floating, and in some cases it 
Is only about 2 to 3 cm In length 


THORAX 

The thorax is long and is more barrel-shaped 
than in the horse or ox, since the ribs are more 



FIGURE 37-15. Sternum of pig; dorsal view. 

1, Manubrium, 2, costal cartilage, 3 , costochondral junc- 
tion, 4, body, 5. fifth nb, 6. xiphoid process, 7, xiphoid 


strongly curved and differ less in relative 
length 

Sternum 

(Figs. 37-15 and 16) 

The sternum consists of six segments and 
resembles that of the ox in general form. The 
first segment (manubrium) is long, flattened 
laterally and bears ablunt-poirtted cartilageon 
its cranial end; its caudal end forms a synovial 
joint with the body. The latter is flattened, 
wide in its middle and narrow at either end. 
The widest segments are formed of two lateral 
parts, which are not completely fused In the 
adult. The last segment has a long, narrow 
xiphoid process which bears the xiphoid carti- 
lage. 


FIGURE 37-16. Sternum of pig; lateral view. 

1 , Manubrium. 2. manubrio»temal »yno\ ial articulation. 
3. utTOOcostal nnlcutation, 4. cmtoehondral Junction. 5. 
fifth rib, 6. xiphoid cartilage 


1222 


pokcine 


APPENDAGES 

by S Sisson* 


BONES OF THE THORACIC UMS 

The thoracic limb of the porcine is composed 
of four chief segments the thoracic girdle 
the arm (humerus) the forearm (radius and 
ulna) and the manus (carpus metacarpus and 
digits [phalanges and sesamoid bones)) For 
anatomical epiphyseal closure times see 
Table 37-1 


Thoracic Girdle (Shoulder) 


The thoracic girdle consists of the scapula 
wta^ualarge w ell developed flat bone that 
presents a small fused coracoid process The 
porcine is devoid of a clavicle however occa 
sionally a small indistinct tendinous band the 
clavicular intersection (regarded by some as a 
0f ,L h \ clav ‘ cle > be found em 

S^” e ‘tu b l d e C r h ' 0CePhaUCUS mUSC ' e CIa 


SCAPU1A 

(Figs 37-17 and 18) 


aw roT-lii 5 Very W,de ,he be: 
aoouti 0 7 The spme is tnangularand is \ 

vMde m its middle, which cunes cau^ 
over the mfraspmous fossa and bears a la" 
tuberosity Its ventral par, bei a smSl^ 


TABLE 37-1 Anatomical Epiphyse/ 
Closure Times in the Pic Thoracic Li 


Proximal 
Distal 
Humerus 
Proximal 
Distal 
Rad us 
Proximal 
Dsul 


Uliu 




3v ty r 

3 JT 
3V, n 


Proximal phalanx 
Proximal 
Dlsial 

Middle phalanx 
Proxl naj 


jecuon (rudimentary acromion) The cranial 
border is strongly convex in profile, sinuous 
when viewed from the front, and thick and 
rough in its middle The caudal border is 
wide slightly concave and bears a rough 
outer lip The dorsal border is convex, and the 
cartilage is not so extensive as in the horse 
and ox The cranial angle is thin and bent 
medially a little The caudal angle is thick 
and approximately a right angle The neck is 
well defined The nm of the glenoid cavity Is 
rounded and not notched The supraglenoid 
tubercle is just above the craniomedial part 
of the glenoid cavity and bears no distinct 
coracoid process it unites with the rest of 
the bone at about one year 


Arm 


(Figs 37-19 and 20) 

The humerus has an appearance m tirofilp 
somewhat hie an italic /m.nu" SbecmStai 
this is because of the marled caudal and 

ends 

Srder SS fcLT" 1 ?, surfa « by a ^Unc, 

The (muscutospiral) g^MveTo^h ‘;! be, ? s '! y 
muscle is shallow tw/j , , lhe brachiahs 
email and StaSta.P, luberwlty is 
midway between it anftl r ° UI,ded eminence 
(lateral tuberosity! n lhe Erea,er '“betcle 

There is a third emmp« a deep groove 

for the attachment of dlstally and laterally 
cle The,ntertub P rl?a! he su P^spmatus mus 
front of the SdirfiSi® 1 ? 1 /* 15 groove is at the 
almost convened fmo “ is un ,^ded and is 
groove on the distal art, 3 ? anal The lateral 
dyle is shallow The nl^ 1 ^ Su 5 face or con 
deep and the plate of v!?' an ? n fossa is very 
from the radud fossa*^!.!'' 1 ’ 10 h separates it 
perforated The Droxim-.i tlU j and s °metimes 
tody at three and a half y™ t 'i ni L e5 '***» the 
year ‘years the distal at one 


’Edited by C R. Ellenpon and reviewed by N 


G Ghoshal 



37 -PORCINE OSTEOLOGY 


1223 


FIGURE 37-17. Left scapula of 
pig; lateral view. 

1, Spine; 2, tuber of spine; 3, aero- 1 
mion; 4, supraspinous fossa; 5, infra- 
splnous fossa; G, cartilage. 




FIGURE 37-18. Left scapula of 
pig; medial view. 

I, Subscapular fossa; 2, serrated 
surface; 3, cartilage. 


Glenoid canty 



1224 


PORCINE 


Greater tubercle 
(Lateral 
••ibemvtxi 



Greater tubercle 
icrantal part t 


epicondjte 

FIGURE 37-19 Left humerus of pig. lateral view 



FIGURE 37-20 Left humerus of pig. media! view 


Forearm 

(Figs 37-21 and 22) 

RADIUS 

The radius is short and narrow, but thick, 
the body increases in sue distally The greater 
part of the caudal surface is ui apposition with 
the ulna this part is marked by a v ascular fur 
row which runs distally from the proximal 
interosseous space and has the nutrient fora 
men at its proximal end The radial tuberosity 
is represented b> a rough area The distal end 
or trochlea is relatively large Us carpal surface 
consists of concavoconvex facets for the radial 
and intermediate carpal bones There is a wide 
shallow groove on the middle of the front The 
proximal end or head fuses with the body at 
one year, the distal at three and a half years 


concurs with the radius in forming the proxi- 
mal interosseous spare of the forearm and is 
marked in its proximal part by the nutnent 
foramen From this space a vascular furrow 
descends to the distal part of the body, where 
there is often a distal interosseous space for 
the passage of vessels The medial surface is 
extensive, concave and smooth The lateral 
surface is slightly convex, and its proximal 
part is marked by an oblique rough line or 
ridge The proximal extremity is large and is 
somewhat bent medially, its length Is more 
than one third that of the entire bone The 
distal extremity is relatively small, it articu 
lates with the ulnar and accessory carpal 
bones and is notched cranially to accommo- 
date the ridge on the radius The bone con 
tains a considerable medullary canal and Is 
consolidated at three to three and a half years 


UINA Manus 

The ulna is massive It is much longer and (Figs 37-23 and 24) 

considerably heavier than the radius, the body 
is curved The cranial surface is convex and CARPAl BONES 
most of it is rough and attached to the radius 

by the interosseous ligament There is a The carpus comprises eight bones, four In 
smooth area on the proximal thud, which each row The bones of the proximal row re- 



37- PORCINE OSTEOLOGY 


1225 


semble those of the ox, with the exception of 
the accessory, which is more like that of the 
horse but has no lateral groove. The first carpal 
is small, elongated from dorsal palmarly and 
rounded and articulates dorsally with the sec- 
ond carpal. The latter is high and narrow and 
articulates with the second and third metacar- 
pal bones dis tally. The third carpal articulates 
with the radial and intermediate proximally, 
the third metacarpal bone distally. The fourth 
is the largest bone of the row; it articulates 
with the intermediate and ulnar proximally, 
the fourth and fifth metacarpals distally, and 
bears a tuberosity on its palmar aspect. 


METACARPAL BONES 

Four metacarpal bones are present. The first 
is absent, the third and fourth are large and 
carry the chief digits, while the second and 
fifth are much smaller and bear the “accesso- 
ry*’ digits. Their proximal ends or bases articu- 
late with each other and with the carpus as in- 
dicated above. The distal ends or heads fuse 
with the bodies at about two years of age. 

The third and fourth metacarpals are flat- 



tened from dorsal to palmar and are three- 
sided and placed close together. The distal end 
or head articulates with the proximal phalanx 
and the sesamoids. The third is the wider of 
the two and articulates with all the distal row 
of the carpus except the first. The fourth ar- 
ticulates with the fourth carpal chiefly, but has 
a small facet for the third. The second and 
fifth metacarpals are placed farther palmarly” 
than the chief bones. The fifth is consider- 
ably the thicker of the two The proximal 
ends are small and articulate with the cor- 
responding carpal and metacarpal bones. The 
distal end is relatively large; its articular 
surface is condyloid dorsally, trochlear 
palmarly. 


DIGITS OF THE MANUS 

Each chief digit comprises three phalanges 
and three sesamoids. The bones of the chief 
digits resemble those of the ox in form, but 
there is no foramen on the axial surface of the 
extensor process and the proximal sesamoids 
are narrow and ridged palmarly. The pha- 
langes of the accessory digits (which do not 


-Olecranon 




1226 


PORCINE 



fourth >Wri»4 

-areal r „ i ^ 1 ln, *«rncaiate carpal C r radial 

psss 



. 0 . ° ,d ," 1 * 1 ■»« -firn .ho- 

rtcic limb of pig, palmar view 

“; h c i“ta„ c ™u ri- "r» 

mofdtar, „ *,„ 


reach the ground ordinarily) are similar in 
form but much smaller Fusion of the prcxl 
mal ends or bases with the bodies tabes place 
at about two years for the proximal phalange! 
and about one year for the middle phalange' 

BONES OF THE PEIVIC IIMB 

The pelvic limb like the thoracic consists of 

four segments the pelvic girdle thigh ffe 
mur and patella) leg (tibia and fibull) and 
pes (tarsus, metatarsus and dieits r„Wo a 
and sesamoid bones]) For anatomiiaUp.phy 8 
seal closure times see Table 37-2 p pny 

Pelvic Girdle (Bony Pelvis) 

The pelvic girdle consists of the ossa cox 
arum (os coxae of both sides) and the sacrum 


co«e' 0f“ach’Sd'e n ’w i hrch 0 r nPO5ed ° f ,h ' 05 
atongthe median tin* a s y nos tosis 
Pelvic n"^ e,V,c symphysis) The 

os COXAE 
(Figs 37-25 and 26) 

nn?i!c°hiu C m me^lmolunlta! wnl Th f 1Uum 

and nearly sagittal In W l Ji eac,10t her 

the lh„ m Lnds h'erad muc T ^t? wln '= ° f 
horse or ox The glutei ^rfi‘ e , SS ?, ha " ln ‘he 

twofossaebyaridge whirMt 8 ? ividcd int0 

the ischiatlc spine ^caudall! T^ ntinU0USWlth 
surface presents m d . y Jh e sacropelvic 
caudally, which is in amv! e u« Slve ^Bh area 
of the sacruni The* smMth ?i? Wlth the wing 
row and is bounded rinra-nt 1 ^ ac area 5s nar 
ores. Is convex and 1, thick, lollhanf^ 



37 -PORCINE OSTEOLOGY 


1227 


TABLE 37-2. Anatomical Epiphyseal 
Closure Times in the Pig Pelvic Limb 


Bone 

Bruni and 
Zimmerl (1951) 

Lesbre (1897) 


1 yr 

-1 yr 

and pubis 

Femur 

Proximal 


3-3 V* yr 

Distal 

Tibia 

3'/a yr 

~3Ya yr 

Proximal 

3V* yr 

~3Vi yr 

Distal 

Fibula 

2 yr 

-2yr 

Proximal 

3Vjyr 

— 3V* yr 

Distal 

2*2Vi yr 

2 2V* yr 

Calcaneus 

Bones distal to tarsus 
(Same as Thoracic 
limb) 


2 2V« yr 


nent in its middle, which forms the highest 
point of the bone The sacral tuber (tuber 
sacrale) is lower than the crest, is directed 
caudally and articulates medially with the 
sacrum. The coxal tuber ( tuber coxae ) is 


lower still and is very little thickened. The 
ischia in the female are somewhat divergent 
and flattened caudally. The tuberaare everted 
and bear three prominences. There is a crest 
or tuberosity on the ventral surface. The 
ischiatic spine is like that of the ox but is 
slightly incurved, and the muscular ridges 
on its lateral face are more pronounced. The 
symphyseal part of the pubis is thick and the 
two bones are almost in a horizontal plane. 
The iliopubic eminence* is prominent, and 
the psoas tubercle is well marked. 

Acetabulum 

The acetabulum is placed a little farther 
caudad than in the ox. The rim is thick and is 
cut into caudally by a narrow fissure, which 
leads into the deep acetabular fossa. The three 
pieces of the os coxae are fused by the end of 
the first year, but the crest and the ischiatic 
tuber are partially separate until the sixth or 


•Prcuss and Budras (1969) assert that the iliopubic emi- 
nence includes both the psoas tubercle and pectineal tuber- 
cle of domestic animals 


Crest o/ i hum Gluteal line 


Ischiatic Lesser ischiatic Ischiatic 
spme , w tch tuber 



Coxat tuber Ilium tbodvt 

Acetabulum Ischium 

FIGURE 37-25. Left os coxae of pic; lateral view. 


Sacral tuber Crest of ilium 



Pub,-. 

urvnml hrunrhl 


I IGLllL 37-2B. Left «» coxae of pijr; medial view. 


1228 


PORCINF 


seventh year The symphysis does not usually 
undergo complete ossification Intenschhl 
bones are present 


PELVIS 


The cranial pel\ic aperture (Inlet) Is ellipti 
cal and very oblique In a sow of full size the 
conjugate (diameter) measures 12 5 to 15 0 
cm and the transverse about 8 75 to 10 00 cm 
In the female the floor (solum) is relatively 
wide and flattened especially at the caudal 
aperture (outlet) where the tubera are evert 
ed it also has a decided ventral inclination 
caudally The pelvic axis is therefore cor 
respondtngly oblique The ischial arch is 
wide In the boar the pubis is much thicker 
and the ischia are not everted caudally The 
ov!f ll f 1 , a 1 p « rlure is Bmaller the conjugate is 
about 110 to 12 5 cm and the transverse 
tourer 7 50 to 8 75 cm The floor 1, con 

w ,t' 0n l S1 £ e 10 s ' de and slopes decidedly 
less then 1„ the tow The IschlaUc .pines m 
more incurved and the ischiatic arch is 
muc h narrower and deeper 


Grtattr 



Trt<cf on 



Thigh 

FEMUR 

(Figs 37-27 and 28) 

body, oS^hi^o^urfalir 11 *? ^ 1( * masslvc 

nized TTie Drinrinii ® ur *® ces nilght be recog 
?ted In the pSSmi ,S!i e "Ht ranien is »l'u 
fee The cauda?snH'Trn°(i h f eranla] sur 


condyloid fossa TKo if j , ere * s no supra 

rather large tubetS ?■' "’“•W side by , 
the ligament of the head of life"? Chracm 0 
neck is distinct Th,?™ . the foniur Thi 
though massive does S?'” Ir0 1 c}Llnt er > a! 
level of the head The Interim* d abovc ,hl 

trad trochanteric fosi «S2KhS' eric cres 
ex. The third trochantePfl ahf] V’S?' oI thl 
of the trochlea are similar and i" ridKC! 
The extremities unite ,vl t h^?£5 S! ‘ aKmal 
three and a half years • ' h bod >' at about 



37 -PORCINE OSTEOLOGY 


1229 


PATEllA 

The patella is very much compressed trans- 
versely and presents three surfaces. 


Leg 

(Figs. 37-29 and 30) 

TIBIA 

The body of the tibia is slightly curved, be- 
ing convex medially. The tuberosity is grooved 
craniaUy, an'd a narrow extensor sulcus sepa- 
rates it from the lateral condyle. The facet for 
the fibula is on the caudal border of the latter 
and is bounded medially by an eminence. The 
proximal part of the cranial border is very 
prominent and curves laterad The distal end 
or cochlea resembles in general that of the ox, 
but is relatively narrower transversely and 
thicker from cranial to caudal. The proximal 
end unites with the body at about three and a 
half years, the distal at about two years. 


F1BUIA 

The fibula extends the entire length of the 
region and is separated from the tibia by a wide 



J ICURE 37-29. Right tibia and fibula of pig; cra- 
nial view. 

Arrow IndictUa extenur groove of the proximal end of 

tibia. 


Medial condyle Intercondylar eminence 



FIGURE 37-30. Right tibia and fibula of pig; cau- 
dal view. 

a. Groove on medial malleolus for tendon of flexor dig!- 
torum longus 


interosseous space. The body is flattened from 
side to side; the proximal part is wide and 
deeply grooved laterally; the distal partis nar- 
rower and thicker. The proximal end is flat- 
tened, grooved laterally and articulates medi- 
ally with the lateral condyle of the tibia. The 
distal end forms the lateral malleolus. It is 
grooved laterally and articulates with the 
tibia and talus medially, with the calcaneus 
distally. The proximal end or head unites with 
the body at about three and a half years, the 
distal at about two and a half years. 


Pes 

(Figs. 37-31 and 32) 


TARSAl BONE? 

The tarsus comprises seven bones. The 
talus and the calcaneus resemble in general 
those of the ox. The axis of the talus is, how- 
ever, slightly oblique (ventromedial), and its 
dtsul end bears a double trochlea for articula- 
tion with the central and fourth ursals. The 
calcaneal tuber is deeply grooved plantarly. 
The central tarsal Is narrow transversely and 



1230 


PORCINE 


Calcaneal tuber 



FIGURE 37-31 Skeleton of right pes of pig, dor 
sal new 


U V Second through fifth digits Mt 2-5 metatarsal 
ra ’4T 3 r PrD: ? ma1, mlddIeand distal phalanges T3 
third and T4 fourth tarsal T c, central tarsal Tf cal 
caneus Tl talus ~ 1 


thick. Its proximal surface is deeply concave 
and the plantar bears a large tubercle The 
first tarsal is high and narrow, it articulates 
with the central and second tarsals and the 
second metatarsal bone The second tarsal is 
smaU and somewhat prismatic, it articulates 
with the central proximally, the third dorsally 
the first plantarly, and the second and third 
metatarsals distally The third tarsal is much 
hu-ger and is compressed from proximal to 
distal, being wide dorsally, narrow plantarly 
It articulates with the centra! tarsal proxi 
mally, the third metatarsal distally, the second 
tarsal medially and the fourth tarsal laterally 
The fourth tarsal is large Its lateral face is 
crossed by an oblique groove for the tendon 
of the fibularis longus muscle The medial 
surface articulates with the central and third 
tarsals The proximal surface supports 
the talus and calcaneus, and the distal sur 
face rests on the fourth and fifth metatarsals 


It ossifies from two centers The summit of 
the calcaneal tuber fuses with the rest of the 
bone at two to two and a half years 


METATARSAl BONES 

The four metatarsal bones resemble the 
corresponding bones of the forelimb but are 
somewhat longer The proximal ends or bases 
of the third and fourth each have a consider- 
able plantar projection, the process on the 
third has a facet for articulation with a discoid 
metatarsal sesamoid bone The second and 
fifth are placed more toward the plantaraspect 
of the large bones than is the case in the fore 
limb 


DIGITS 

The proximal and middle phalanges are a 
little longer and narrower than those of the 
forehmb 



tar view 

tal phalanew 3 middle and die 

=£27? SSKSWZ, 



37— PORCINE OSTEOLOGY 

SKULL 


1231 


by D J Hillmann 


OCCIPITAl BONE 

(Figs 37-33, 34, 35 and 41/G) 

The occipital bone forms the caudal aspect 
of the skull In the pig it is somewhat flattened 
and elongated In its middle ventral part it is 
perforated by the large, roughly trapezoidal 
foramen magnum (Figs 37-33 to 35) which is 
flanked laterally by the occipital condyles and 
dorsally by the prominent paired nuchal tuber 
cles 

The basilar part is hexagonal flattened cau 
dally, narrower, and thicker rostrally The ex 
temal surface is marked by a narrow median 
ndge, the pharyngeal tubercle. Ventrolaterally 
the basilar part presents prominent paired 
muscular tubercles which converge rostrally 
as they taper onto the basisphenoid bone Ros 
trolateral to the muscular tubercles the right 
and left sides are rounded and concur m the 
formation of the jugular foramen caudally and 
the foramen lacerum rostrally The caudolater 
al sides of the basilar part are fused with the 
lateral parts of the occipital bone and also con 


tribute to the formation of the occipital con 
dyles The caudal side is notched and enters 
into the formation of the foramen magnum 
The cranial or cerebral surface is flat and 
smoothly concave conforming to the surface 
of the medulla oblongata and the pons 
The paired lateral parts flank the foramen 
magnum, enter into the formation of the nu 
chal tubercles and laterally form a fan shaped 
projection which surrounds the occipital con 
dyles Each part overlaps and fuses with the 
occipital process of the temporal bone Ven 
trally each lateral part presents a distinct 
elongated jugular process (Fig 37-35/27) 
Rostromedial to the base of the process, it is 
marked by a vertically elongate, jugular notch 
In conjunction with the tympanic part of the 
temporal bone, it forms the jugular foramen 
Immediately caudal to this opening is the ex 
temal opening of the canal for the hypoglossal 
nerv e Caudomedial to the base of the process 
is the deep ventral condylar fossa Internally, 
each lateral part presents a strong depression 
on its rostrolateral surface which marks the 


FIGURE 37-33 Skull of pig cnudal 
view 

12 3 Squamous lateral and basilar pans 
of occipital bone 4 foramen magnum 5 oc 
cipttal cond>le C Jugular process 7 squa 
mous part of temporal bone S external 
acoustic meatus 9 articular tubercle of 
temporal bone 10 zygomatic process of 
maxilla 11 tympanic bulla 12 12 perpen 
dicular and horizontal parts of palaUne 
bone 13 13 choanae 14 \omer 15 
pterygoid process of basisphenoid bone 16 
pterygoid process of palatine bone 17 con 
dylar process of mandible 18 mandibular 
foramen ID body of mandible 


A ucf ul mat 






37- PORCINE OSTEOLOGY 


1 


In the adult, the frontal and sphenoidal 
sinuses extend into the squamous and basilar 
parts, respectively 

SPHENOID BONE 

(Figs 37-35 and 41 /H) 

The sphenoid bone is situated in the base of 
the cranium its central part lying rostral to 
the basilar part of the occipital It consists at 
birth of two distinct parts, the basisphenoid 
and the presphenoid 

Basisphenoid bone 

The basisphenoid is composed of a body, a 
pair of wings and a pair of processes The body 
articulates caudally with the basal part of the 
occipital bone The wings articulate lat 
erally with the squamous part of the temporal 
bone and rostrally with the presphenoid cau 
dally, there is a limited connection with the 
internal surface of the parietal bones The 
pterygoid processes articulate rostromedial 
ly with the presphenoid rostroventrally with 
the palatine bones and medially with the ptery 
goid bones 

The body, compressed laterally and some 
what triangular, presents a low sagittal ndge 
on its ventral surface In the pig there is a dis 
tinct sella turcica limited caudally by the 
prominent dorsum sella which slopes caudally 
to join the basal part of the occipital bone A 
shallow depression formed at this point and 
termed the clivus supports the pons Project 
in g in a rostrolateral direction from the dor 
sum sella are the paired caudal clinoidal proc 
esses Depending on the age and specimen 
preparation they may or may not be observed 
Rostrally, the dorsal surface of the basisphe 
noid concurs with the presphenoid in the for 
mation of the deep hypophyseal fossa. 

The wings of the basisphenoid extend from 
tile body,at first laterad and then cur\ e sharply 
dorsal to articulate with the squamous part of 
the temporal The temporal surface faces 
caudoliterally and enters into the formation 
of the infratemporal fossa. A shallow groove is 
found on the \ cntromedial aspect of the wing 
at the base of the pterygoid process Rostrally 
the groov e becomes the pterj gold canal which 
is formed medially b> the \erticai part of the 
pterygoid and the presphenoid bones and lat 
enliy by the pter> goid process of the basisphe 
noid. The rostral part of the canal opens into 
the caudal part of the pterygopalatine fossa 
between the presphenoid ro strom ediall} and 
the pterygoid process caudolatcraU) The ca 
nal transmits the nerve of the ptery goid canal 
The cerebral Hurface of the wing presents two 
longitudinal grooves and two ridges The most 
lateral ridge Is the rostral continuation of the 
tentorial process of the parietal bone At the 


junction of the basisphenoid and presphenoid 
the process terminates A small rectangular 
portion lateral to this process faces into the 
middle cranial fossa Medial and ventral to the 
ndge is a ventrally directed shallow groove 
the sulcus n maxillaris, which opens rostrally 
and concurs with the presphenoid in the for 
mation of the foramen orbitorotundum Cau 
dally, this lateral groove is notch°d laterally by 
the spinous incisure and medially by the oval 
incisure The most medial groove is shallow 
and separated from the lateral groove by a 
short longitudinal ndge which extends caudal 
]y toward the petrous part of the temporal bone 
and incompletely separates the carotid inci 
sure medially from the previously mentioned 
incisures laterally The medial groove contains 
the cerebral rete and cavernous sinus 

The pterygoid process extends ventrally 
from the body and wing of the basisphenoid 
In its proximal part it is concave rostrally, 
unites medially with the presphenoid, and lat 
erally presents a thickened pterygoid crest 
From this part the pterygoid process twists 
laterally and articulates with the palatine 
bone rostroventrally and pterygoid bone medi 
ally Dis tally on its caudal surface, is a deep 
depression which concurs with the pterygoid 
bone in forming the pterygoid fossa The alar 
foramen is absent The pterygoid process is 
variably excavated for the sphenoid sinuses 

Presphenoid Bone 

The presphenoid is composed of a body and 
a pair of wings The body articulates with the 
basisphenoid caudally, the ethmoid rostrally, 
the vomer ventrally and the palatine ventro- 
laterally, the wings articulate with the frontal 
rostrolaterally and with the wings of the basi 
sphenoid caudolaterally 

The bodj situated medially, is short and 
laterally compressed Ventrally it is concealed 
to a large extent by the vomer and pterygoid 
bones The cerebral surface presents the fol 
lowing features (1) Rostrally there is a raised 
flattened part (jugum sphenoidale) which pre 
sents two slightly concave lateral areas, this 
part has a caudal thin free margin which ov er 
lies the entrance to the optic canals (2) Just 
caudal to this and at a lower level is a smooth 
transverse depression, the optic groove (sul 
cus chiasmatis ) on which the optic chiasmi 
rests From each end of this groove the optic 
canal passes rostrad and laterad and opens into 
the orbit at the optic foramen. Rostnll), the 
body is expanded to receive the ethmoid lab> 
nnth and perpendicular lamina of the ethmoid 
bone It Is excavated to form the sphenoid 
sinuses As the animal ages the excavation 
proceeds such that onl> a thin plate of bone 
remains between the middle cranial fossa and 
the sphenoidal sinus Rostroventrally, the op- 



1234 


PORCINE 


tic groove is deepened by another groove 
which transmits anastomotic branches of the 
internal ophthalmic arteries (3) Caudal to the 
sulcus chiasmatis the body of the presphenoid 
is elevated forming the <£tuberculum sellae 
It slopes caudally concurring with the basi 
sphenoid in the formation of the rostral floor 
of thehjpophyseal fossa. 

The wings of the presphenoid curve dorso 
laterally from the sides of the body The cere- 
bral surface is convex and is marked by digital 
impressions for the gyn of the cerebrum The 
orbital surface is concave The toot of the 
wing is perforated by the optic canal Caudal 
to the optic canal a blunt ndge divides it from 
the medial wall of the foramen orbitorotun 
dum w hich is thus formed by the concurrence 
of the presphenoid and basisphenoid Internal 
l* the dorsal wall of the foramen orbitorotun 
dum is bordered by th e sharp caudal projection 
of the wing of the presphenoid. Lateral!) this 
projection is continued caudally on the wing 
of the presphenoid Medially the crest pre 
sctits in a variable manner the slender rostral 
ehnoida! processes 


ETHMOID BONE 
(Figs 37 36 to 41/J) 

The ethmoid bone is located deep within the 
skull between the cranial and facial parts It 
lies between the right and left orbital fossae 
and is partiall) surrounded by excavations of 
the nasal cant) Further it is situated within 
the fundus of the nasal cavity where its nu 


merousbony scrolls increase the surface area 
and appear to restrict and direct the circula 
tion of air within the paranasal sinuses In the 
immature specimen the ethmoid fuses with 
the vom er thus making it difficult to disarticu 
late it as a separate bone It also fuses early 
with the presphenoid In addition it relates to 
the frontal maxilla and palatine bones (Figs 
37 36 and 37) It is composed of paired laby 
nnths (lateral masses) paired orbital and 
cribriform plates and a median perpendicular 
plate 

Each labyrinth is composed of approximate 
ly 20 delicate bony laminae the ethmoturbi 
nates which are arranged in a parallel manner 
extending from the orbital plate (lamina) to 
the cribriform plate Upon each lamina is a 
vanable number of primary and secondary 
bony scrolls The long axis of each scroll is 
perpendicular to the surface of the cribriform 
plate thus permitting the olfactory nerves to 
enter the olfactory bulb at approximately 
nght angles over its entire surface 

Only seven of the ethmoturbmates are well 
developed and extend close to the midline or 
perpendicular plate these are called endotur 
binates (Figs 37-38 and 39) The intervening 
13 (plus five to seven poorly developed lami 
nae frequently only a single scroll) are desig 
nated ectoturbinates 

The basal lamina of endoturbinate I (dorsal 
nasal concha) (Figs 37 40 4J/K and 44/1) 
arises from the dorsomedial surface of the 
orbital plate It is unique being scrolled on one 
surface (laieroventral) only the other (dor 
somedial) surface is smooth and forms the 



FIGURE 37 36 Transverse sec 
lion through ethmoidal labyrinth and 
surrounding paranasal sinuses of 
Pig Section taken between molar 
two and three 


. maxilla 3 zygoma 

lie bone 6 lacrimal bone A medial ros- 
tral Jronta] tlnu* <left side) Note both 
compartments forming one sinus with a 

lain na separating them B caudal frontal 

sinu* (left side) C rostral frontal * n US 
(left side) G lacrimal sinus H H maxil 
, I 7 * nus Spearing as a medial and a 
I ethmoidal cells 
(left s de) J maxillary sinus (see Fie 
37 u ? omeT M third molar {level 
at which the section wa* taken) (From 
Hillmann 1971) ^ 



37— PORCINE OSTEOLOGY 




FIGURE 37-37. Transverse sec- 
tion through nasal cavity and para- 
nasal sinuses of pig. Section taken at 
level of second molar. 

I, Frontal bone, 2, maxilla; 2’, infraor- 
bital foramen; 3, zygomatic bone, G, la- 
crimal bone (note presence of lacrimal 
canal beneath no), 11, basal lamina of 
ethmoid bone fused with vomer; (these 
structures together form the horizontal 
septum between the fundus of the nasal 
cavity (abovel and the nasopharynx 
(below]), A, medial rostral frontal sinus 
(right side), B, caudal frontal sinus (right 
side), C, lateral rostral frontal sinus 
(right side), G, lacrimal sinus (either side 
of G) (right side), H H, maxillary sinus, 
black, lateral compartment, white, medial 
compartment (dotted line indicates com 
mu ideation), I (center), ethmoidal cells, 

J, sinus within zygomatic bone which 
later communicates with maxillary sinus 
(H) Note in this specimen this sinus is, 
within the zygomatic bone, completely 
independent of the maxillary smus, K, 
nasopharynx, M„ second molar, I (left), 
dorsal nasal concha (endoturbinate I), II, 
middle nasal concha (endoturbinate II) 
Arrows indicate communications of the 
paranasal sinuses with the nasal cavity 
through the ethmoidal labyrinth (From 
HiUmann, 1971 ) 



floor of the primitive frontal sinus (Fig. 3^- 
39/5’) and eventually a nasofrontal opening. 
Extending from the basal lamina, there are 
four ventrolaterally directed scrolls, with 
the terminal scrolling being different from 
the others. Caudally the medial face of 
the terminal scroll appears to arise from the 
cribriform plate as a narrow shelf of bone. It 
extends rostrally, gradually widening until, at 
a level between the first and second molar 
teeth, its width is approximately double. Lo- 
cated at the level of this enlargement is the 
cavity (variable in size) of endoturbinate 1 
(Figs 37-41/k) which, from its lateral and dor- 
sal surfaces, remains m communication with 
the nasal cavity. The cavity is part of the dorsal 
conchal sinus Laterally, the endoturbinate 
presents a thin horizontal shelf of bone which 
fuses to the medial surface of the maxilla 
and forms the roof of the caudal part of the 
middle nasal meatus. Projecting rostrally, 
and continuing the flattened medial face of 
the endoturbinate, is a narrowed projection 
which continues along the crest of the nasal 
bone with which it completes the form of the 
dorsal nasal concha 

Endoturbinate II (Figs. 37-38, 39, 40 and 
41/L) is much smaller than the first; compara- 
tively it is designated as the middle nasal con- 
cha. The basal lamina of endoturbinate II, the 
tenth in succession starting with the first 
endoturbinate, takes origin from the part of 
the orbital plate which forms the medial wall 
of the maxillary sinus. It presents small sec- 
ondary scrolls on both surfaces and ends in a 
paired terminal scroll. 

The basal laminae of endoturbinates III to 


VII (Figs. 37-38 to 41/N) are set so that they 
are oriented ixt an oblique angle to the midline. 
They are directed caudolaterad. They present 
secondary scrolls on both surfaces, the num- 
ber decreasing from endoturbinates III to VII. 
Endoturbinates III to V end in paired terminal 
scrolls; endoturbinates VI and VII end in sin- 
gle terminal scrolls (the numbers of scrolls, 
both secondary and terminal, may vary). 

All of the ectoturbinates are similar in origin 
and structure, but only ten are well developed 
and somewhat constant. The majority of the 
well developed ectoturbinates are located be- 
tween the laminae of the first and second en- 
doturbinates. Of these, some extend closer to 
the midline (similar to the endoturbinates) but 
fail to reach it, and arrange themselves in a 
medial and a lateral series. Only the larger 
laminae are constant. 

The orbital plate represents a thin, incom- 
plete, primarily lateral covenng of the laby- 
rinth. Its dorsomedial part (the roof plate) is 
small and unites medially with the perpen- 
dicular plate of the ethmoid Its ventromedial 
part (the floor plate) is thicker and more exten- 
sive. Medially, it unites with the vomer, later- 
ally, it unites with the maxillary bone to com- 
plete the floor of the fundus of the nasal cavity, 
and caudally, it unites with the palatine bone. 
Its rostral edge is smooth and forms the demar- 
cation between the fundus of the nasal cavity 
dorsally and the nasopharynx ventrolaterally. 
The ventral surface is grooved and, together 
with the palatine and maxillary bones, com- 
pletes the formation of the sphenopalatine 
foramen. Laterally, the orbital plate presents 
an irregular surface Its caudoventral part is 



1236 


PORCINE 


smooth and com ex and continuous caudally 
with the presphenoid forming the dorsomedial 
surface of the pterygopalatine fossa The ros 
trodorsal part can be divided into two portions 
-dorsally it presents a shallow groove which 
represents the medial wall of the nasomaxil 
lary aperture caudally the groov e curves ven 
trally and is continuous with the medial wall 
of the maxillary sinus formed by the deep cir 
cular concavity of the ventral portion 
The perpendicular plate is an ossified sheet 
situated between the two labyrinths and 
serves to unite the nght and left cnbnform 
plates It is composed of compact bone which 
results from a progressive ossification of the 
cartilaginous nasal septum Ventrally it is 
fitted into a groove located in the vomer It 
fuses with the presphenoid bone caudally at 
an early age but does not uniformly fuse with 


the vomer at the same age Therefore in the 
macerated bones there exists a canal immedi 
ately ventral to the lamina which persists in 
the adult It contains small blood vessels 
which enter the cartilage of the nasal septum 
Caudally on the lateral surface it presents 
numerous depressions corresponding to en 
doturbinates IV to VII A dorsal extension the 
strongly developed cnsta galli, exists between 
the cribriform plates Eventually the cnsta 
galli fuses rostrally on the midline with the 
frontal bone 

The cribriform plate is paired and separated 
by the medial dorsal extension of the perpen 
dicular plate the cnsta galli In the immature 
animal, where the ethmoid is easily removable 
a smooth ndge exists around the periphery, 
the perforated portion is concave from side to 
side and end to end. Caudally, its surface (cnb- 



3 ‘“ 38 Macerated skull of 
10 to 11 mo old female pig sagittal 
sections— craniofacial region 

Naial bone disarticulated perpendic 
ular plate of ethmoid bone sculptured to 
Illustrate ethmoidal labyrinth Vewum 
f *phenoldalium removed to U 
rr™*«f XCa ' a 1 lon °f * ‘n u s vomer partly 
ri™ nV 1 arT0WS indicate communica 
‘ Wlth nasal 
^r^L P<,nl ? n 1 ,yfns wi,hln nasal 

d °tted Portion 
ring beneath bone or tissue broken line 

S-Tb sTrr ° f “ P— saUmS 

lop right side bottom left s de A me 

5 ? audal fron ‘ 31 sinus (greatly 

D soheLS “T™ 1 ro ’ fral ^maUinu 7 
D sphenoldat ,inu, i frontal bone 2 
R^wllafnasomaxlllary su t ure) 4 ventral 
nasal concha 5 eihmoidbone 7 palatine 
^mJH P u n ' > 'i hm0idal l*mlM) 8 
MrilwM b °" e , 9 P rts P h *noid bone 10 
11 basailamma 12 per 
1 ^n^oturbinate'T 

fmntal sinus extends toward the muri 
bones (From HUImann 107| ) * 



37 -PORCINE OSTEOLOGY 


1237 


FIGURE 37-39 Macerated skull of 
10 to 11 mo old female pig, sagittal 
section- craniofacial region 

Nasal bone disarticulated perpendic 
ular plate of ethmoid bone sculptured to 
Illustrate ethmoidal labyrinth septum 
sinuum sphenoidakum removed to il 
Uistrate excavation, of sinus vomer partly 
removed arrows indicate communication 
of paranasal sinuses with nasal cavity- 
solid portion lying within nastd cavity or 
paranasal sinus dotted portion lying be 
neath bone or tissue broken line indicates 
limitation of a paranasal sinus Top right 
side bottom left side B Caudal frontal 
sinus (left side) (top- septum sinuum 
frontalium to left of midline) B rostral 
extension of B D sphenoidal sinus 1 
frontal bone 2 maxilla (nasomaxillary 
suture) 4 ventral nasal concha 5 
ethmoid bone 5 ethmoidal meatus with 
surrounding lamina (Note fine line of 
fusion of delicate ethmoidal lamina with 
the frontal bone) 7 palatine bone (sphen 
oethmoidal lamina) 8 pterygoid bone 9 
presphenoid bone 10 parietal bone 11 
basal lamina 12 perpendicular lamina I 
endoturbinate I II endoturbinate II 
III VII endoturbuiates III to VII This 
specimen illustrates a normal sized (for 
this age) caudal frontal sinus The rostral 
projection (B ) arises primarily from the 
left caudal frontal sinus (B) (From Hill 
mann 1971 ) 



nform plate) lies m a horizontal plane From 
here, rostnlly, it curves dorsally until it lies m 
a vertical plane It is perforated by well over 
one thousand foramina Some of these are 
quite large and arranged around a crest which 
corresponds to each basal lamina of the eth 
moidal labyrinth 3ustlateral to the cnsta galli 
Is a row of large foramina possessing smaller 
secondary foramina within the primary larger 
one (This arrangement accounts for the ex 
trcmely large number of foramina) Parallel to 
the medial row is an additional senes of fora 
mlna that are not as uniform in their arrange 
mem Within the surface of the cnbriform 
plate is a smooth, non perforated crest which 
corresponds to the basal lamina of endoturbi 
mate II Continuous with the crest slightly 
rostrodorsally is a smooth elevated area de 


void of foramina which radiates laterad and 
represents the last area of the cnbriform plate 
to ossify It bndges the basal attachment of 
endoturbinate I and isolates all the ethmotur 
binates occumng prior to that of endoturbi 
nate II 

INTERPARIETAL BONE 

The interparietal bone fuses before birth 
with the occipital The internal occipital pro- 
tuberance Is absent 

PARIETAL BONES 
(Figs 37-34, 35 and 42) 

The parietal bones arc paired A distinct 
temporal line divides the external surface into 



1238 


PORCINE 






FIGURE 37-40 A Left side of 
sagittal section of female swine skull 
(mature specimen) 

4 Ventral nasal concha 5 ethmcrid 
bone 7 palatine bone 1 1 basal lamina 
A, caudal frontal sinus D sphenoidal 
sinus F dorsal conchal sinus 1 endo- 
turbinate I II endoturbinate II HI VII 
endoturbinates III to VII 


D Perpendicula. plate of ethmoid 
bone sculptured to illustrate naso- 
frontal communication. 

Septum slnuum sphenoidalium (D) re 
moved to illustrate excavation of sinus 
vomer partially removed. Arrows indi 
cate communication of paranasal sinuses 
with nasal cavity-solid lying within 
nasal cavity or paranasal sinuses dotted 
lying beneath bone or tissue (From Hill 



FIGURE 37-41 Right side of sagittal section of mature swine skulL 


— u, luaiure swine bkuii. 

Skull has been sculptured to Illustrate nasal cavity and paranasal sinuses A Incisive bone r t „ 

palatine bone E. pterygo d bone F frontal bone G occipital bone H sphenrfd C maxilla D 

vomer (rostral pan removed) J ethmoid bone K dorsal nasal concha L. middlenaL cine ha 1 

N ethmoturbinates I first Incisor PM first premolar M first molar f eaiMst i Jr" 3 r v. v * ntraI “sal concha 
the left side thus a deviated frontal sinus septum) and f right s.de (arrow « pi„i^ tSgh tiie .InuTi^^T 
Ually remov ed frontal sums septum) g medial rostral frontal sinus h, sphenoidal sinus (arrow Lsrine > tfellSk ? p “- 
s nus 3 k nure thus communicating with the fundus of the nasal cavity) i ethmoidal cells sphenoid 

ventral nasal conci a (dorsal scroll and correspond ng recess) and m (ventral scroll »nH I 11 * d orsa] conchal sinus rn 

ine sculptured basal lamellae above 3 m arrow #3 lead ng to sinus n sphenopiatine S o" i'S S 
arrow 2 represen s communication pa hvvay from nasal cavity into dorsal conchal sinus (kland caudal froSralri™. ,rv 
arro v 3 represents communication pathway from nasal cavity into ventral concha! sinus (mi * lnu * (r > 

municauon pathway from nasal cavity into lateral maxillary JLs (nasomaxlllary^penure) (From wAtmrntf 0 ” 



37 -PORCINE OSTEOLOGY 


1239 



A Occ pital bone B squamous part of temporal bone C parietal bone D frontal bone E lacrimal bone F zygomatic 
bone G max lla H incisnebone I nasal bone J rostral bone K mandible 1 occipital condyle 2 jugular process 3 
condylar process of mandible 4 external acoustic meatus 5 temporal fossa 6 parietal crest 7 zygomatic process 8 or 
bital part of frontal bone 9 fossa for origin of ventral oblique muscle of eyeball 10 orbital opening of supraorbital canal 
11 lacrimal foramina 12 supraorbital foramen and groove 13 infraorbital foramen 14 zygomatic process of temporal 
bone 15 frontal and 15 temporal processes of zygomatic bone 16 incisor teeth 17 canine teeth 18 18 premolars 19 
19 molars 20 mental foramina 21 mental prominence 22 angle of mandible 


a dorsal flat parietal plane and a lateral flat 
temporal plane The parietal plane is limited 
medially where it joins the bone of the oppo 
site side by the short straight sagittal margin 
rostrally it joins the frontal bone at the long 
curved frontal margin caudally it joins exten 
sively with the occipital bone at the occipital 
margin The temporal plane forms a large part 
of the temporal fossa caudally it blends with 
the occipital bone in the formation of the dis 
tmct nuchal crest (Fig 37-33) and ventrally 
is overlapped by the squamous part of the 
temporal at the extensive squamosal margin 
The internal surface is cpncave It presents 
numerous digital impressions which corre 
spond to the cerebral gyn There are also 
furrow s for the meningeal artenes Van 
ably along the sagittal border is a shallow 
groove for the dorsal sagittal sinus Ventro 
caudally is a medial projection which contnb 
utes to the formation of the osseous tentorium 
cerebclli which separates the medial and 
caudal cranial fossae The Internal sagittal 


crest is greatly reduced In the adult the bone 
is usually excavated by the frontal sinus The 
temporal meatus is absent in the pig 

FRONTAL BONES 

(Fig 37-4 1/F) 

The paired frontal bones are interposed be 
tween the panetal bones caudally (parietal 
margin) and the nasal bones rostrally (nasal 
margin) They articulate with the ethmoid, 
lacnmal wings of the presphenoid and basi 
sphenoid maxilla and the squamous part of 
the temporal They are irregular and con 
sist of squamous nasal and orbital parts 

The squamous part (Figs 37-34 and 42) 
forms the basis of the forehead is thick and 
excavated by the frontal sinus Its external 
surface is smooth and vanes from convex to 
concave depending on the breed Laterally it 
is bordered b> a semicircular supraorbital 
margin separating it from the orbital part. Ap- 
proximately two thirds of the distance rostral 



1240 


PORCINE 


ly and centrally on each bone is the supraorbi- 
tal foramen (the external opening of the 
supraorbital canal) which leads obliquely 
cau dally to open into the medial wall ot the 
bony orbit at its dorsal part In the mature ani 
mal the canal is surrounded by the paranasal 
sinuses The supraorbital groove continues 
rostrally from the foramen onto the nasal 


moid laminae Between the«eare deep cxcava 
tions which represent the extension or the 
ethmoid meatuses of the ethmoid bone Into 
the frontal bone forming the frontal alnuses 
The frontal sinuses of the right Eide are sepa- 
rated from those of the left side at the sagittal 
margin by the septum slnuum frontahqm 


The nasal part is a small rostral portion 
which fuses with the nasal bone at the nasal 
border 

The zygomatic process is located at the cau 
dolateral portion of the bone and projects in a 
ventrolateral direction It is short and rounded 
and lacks connection with the zygomatic arch 
The orbital part is extensive and forms the 
greater part of the medial wall of the orbit Its 
dorsal part is perforated by the orbital onfice 
of the supraorbital canal, rostral to which is 
the distinct trochlear fovea for the trochlea of 
the obhquus dorsalis muscle of the eye The 
ethmoidal foramen is situated in the ventral 
part, near the junction with the wing of the 
presphenoid bone Immediately caudal to the 
ethmoid foramen the orbital part is notched by 
the sphenoid notch to receive the wings of the 
pre and basisphenoid bones, caudal to the 
sphenoid notch the orbital part presents a 
thick projection (visible only in the disarticu- 
lated bone) which is overlapped by the squa 
mous part of the temporal bone 
Viewing tht frontal bone laterally, a large 
rostroventrally directed notch, the ethmoid 
notch, formed at the rostral edge of the orbital 
part and ventral to the rostral part of the squa 
ma, receives the lacnmal bone * 

The temporal surface is very small and lies 
caudal to the zygomatic process 

In the disarticulated bone the internal Bur- 
face is divided into two parts The caudal part, 
the rostra] cranial fossa (Fig 37-41), is further 
subdivided by a thick transverse ridge, the 
ethmoidal margin, into two unequal portions - 
the larger being the rostral cranial fossa proper 
and the smaller, the rostral poruon, which 
contributes to the ethmoidal fossa which 
houses the oiractorybulbs. The concave rostral 
cranial fossa proper is marked by distinct digi 
tal impressions conforming to the cerebral 
gyn Rostrally, the rostral cranial fossa is 
limited by a shallow transverse ndge which, 
in the adult, fuses with the ethmoid bone 
to complete the formation of the ethmoidal 
fossa Opening into the ventrolateral part 
of the ethmoid fossa is the ethmoid fora- 
men which transmits the ethmoid nerve and 
artery The rostral part of the internal surface 
is deeply concave, beset with oblique parallel 
ridges or septa which correspond to the eth 


•A portion of the ethmoidal labyrinth i» housed deep to 
this notch 


TEMPORAL BONES 
(Figs 37-34, 35 and 42) 

The temporal bones form part of the lateral 
wall of the caudal cranial fossa Each is situ- 
ated between the occipital caudally.thc parie- 
tal dorsally, the frontal rostrodorsally and the 
basisphenoid Tostrovcntrally. It also articu- 
lates with the mandibular condyle and the 
hyoid, the zygomatic process joins the zygo- 
matic bone It consists In the young pig of 
three distinct parts, squamous, tympanic and 
petrous 

The squamous part, the largest, articulates 
with all of the previously named bones except 
the hyoid It is an Irregular bone with two sur- 
faces and four borders 
The occipital process arises from the caudal 
part of the squama. Its lateral surface presents 
the temporal crest, which here forms the lat- 
eral limit of the temporal fossa. 

The cerebral surface is small It Is divided 
by the tentorial process of the parietal bone 
into a rostral part, which forms a small part or 
the ventrolateral wall of the middle cranial 
fossa, and a caudal part, which forms a small 
part of the lateral wall of the caudal cranial 
fossa. The rostral part presents a groove for 
the middle meningeal artery 
The temporal surface is small and convex, 
and presents a distinctly pointed rostral pro- 
jection From its ventral part arises the zygo- 
matic process which forms the lateral bound 
ary of the ventral part of the ventral portion 
of the temporal fossa. The process is at first 
directed laterally and is wide and flattened 
dorsoventrally It then turns rostrad, becomes 
narrower, and is twisted so that its free sur- 
faces are media! and lateral Rostroventro- 
laterally, the zygomatic process articulates 
with the temporal process of the zygomatic 
bone forming the zygomatic arch. The media! 
surface is concave, the lateral surface is short 
and convex Its dorsal border is sinuous and 
cap dally continuous with the temporal crest 
roslrally it fails to articulate with the zygol 
mafic process of the frontal bone, resulting 
in an incomplete bony orbit The wide caudal 
part presents on its ventral face a surface 
for articulation with the condyle of the 
mandible This surface consists of a trans- 
versely elongated, shallow articular tubercle, 
caudal to which is the shallow triangular 
mandibular fossa whose apex is directed 
dorsally. The fossa is limited caudally by 



1241 


37- PORCINE OSTEOLOGY 


a greatly Teduced retroarticular process 
The temporal meatus and retroarticular fora 
men are absent 

The parietal (dorsal) border of the squamous 
part articulates with the parietal bone, form 
ing the squamous suture The frontal (rostro 
dorsal) border unites with the frontal bone at 
the squamosofrontal suture The sphenoidal 
(rostxoventral) border joins the wing of the 
basisphenoid at the sphenosquamous suture 
Caudally, the squama articulates in large part 
with the occipital, ventrally, it is intimately 
related medially to the petrous part and lat 
erally to the tympanic parts of the temporal 
bone 

The petrous part of the temporal bone is 
relatively small and irregular in shape It is 
placed between the occipital caudally the 
parietal rostrodorsally and the tympanic part 
latero ventrally, and is overlapped by the squa 
mous part laterally 

The medial surface faces into the caudal 
cranial fossa It is irregular and dense Dorsal 
ly it is concave and presents a cerebellar fossa 
of variable depth, centrally is the entrance to 
a short canal the internal acoustic meatus, 
which transmits the facial and vestibulo 
cochlear nerves The entrance to the meatus is 
termed the porus acusticus internus The fun 
dus of the meatus is divided by a crest into a 
rostral and a caudal fossa Caudal and slightly 
dorsal to the meatus and near the caudal mar 
of the surface is the external opening of 
the \estibular aqueduct Ventral to this is a 
small openmg leading to the cochlear canal 
The petrosal part lacks a crest which con 
tributes to the formation of the osseous ten 
tonum cerebelh 

The mastoid process is greatly reduced The 
stjloid process is an oval short slim rod reach 
mg a length of about 0 5 cm which is fused 
With the lateral caudal wall of the tympanic 
bulla. It is connected by a bar of cartilage the 
tympanohyoid witn the stylohyoid bone The 
stylomastoid foramen (Fig 37-35/30) the ex 
te ™ a I opening of the facial canal through 
which the facial nerve emerges is incom 
pletely separated from the styloid process by a 
shelf of bone 

The tympanic part is ventral to the petrous 
The tympanic bulla a distinct feature of 
the tympanic bone is elongate and laterally 
compressed with an abbreviated muscular 
process directed ventrally from its rostral 
e ”8 e The tympanic cavity is small and commu 
nicates in its ventral wall with the cancellous 
interior of the bulla The tympanic part is com 
Pleted in its formation by die elongate narrow 
external acoustic meatus surrounded by the 
tympanic incisure of the squamous part of the 
temporal bone The meatus which lies in 
close proximity to the temporal crest is di 
reeled lateral!} dorsnlty and slight!} rostraliy 


ending in a rough edge immediately caudal to 
the apex of the zygomatic process of the tern 
poral bone 

The sphenoid sinus variably extends caudo- 
laterally into the squamous part of the tempo 
ral bone 

VOMER 

(Figs 37-41/1 and 43/C) 

The vomer is a median bone which assists in 
forming the ventral part of the nasal septum 
It is very long Its rostral extremity almost 
reaches the body of the incisive bone and is 
pointed Caudally, it extends (o the level of the 
presphenoid, whose body it partly conceals 
Throughout its length it is distinctly grooved 
(septal sulcus>on its dorsal surface to receive 
the cartilage of the nasal septum, caudally, it 
receives the osseous perpendicular lamina of 
the ethmoid bone 

Ventrally, it tapers to a sharp edge, the ros 
tral quarter of which is modified for articula 
tion with the palatine process of the incisive 
bone, its middle half is received into a groove 
formed by the nasal crest of the palatine proc 
ess of the maxillae and the horizontal plate of 
the palatine bone Caudally this relationship 
contributes to the formation of an extended 
osseous septum between the nght and left 
nasopharyngeal meatuses Its caudalmost 
part is concave 

The caudal half of the vomer articulates 
with thr^e bones (1) The rostral third of this 
articulation is m the form of a laterally pro- 
jecting wing which fuses at a very early age 
with the basal lamina of the ethmoid bone 
This early fusion results in a horizontal lamina 
separating the nasal fundus dorsally from the 
elongate nasopharyngeal meatus ventrally 
(2) In its middle third the vomer articulates 
ventrolaterally with the perpendicular part of 
the palatine bone (3) The caudal third articu 
lates laterally with the expanded rostra] part 
of the body of the presphenoid That part of 
the vomer within the nasal fundus presents 
grooves and ndges on its lateral surface cor 
responding to the ethmoidal concha and 
meatuses 


MAXIUA 

(Figs 37-34 35 41/C and 42) 

The maxillae are the principal bones of the 
upper jaw and carry the upper cheek teeth 
They are situated on the lateral aspect of the 
face and articulate with the incisive bone 
rostraliy, nasal bone dorsomedially frontal 
bone caudodorsomedially lacrimal bone cau 
dally zygomatic bone caudolaterally, palatine 
bone caudoventromediallj, ethmoid bone me 
dially and \ entral nasal conchal bone internal 



1242 


PORCINE 





j-rw t i > | A , 4 

i'll II hid I III I 111 i.tif I 


FiuUKE 17-13 Tranvrtr»e sections through na»»I tavlty of mature pig at lrvfl of second prtrnoUr 

F Natal bone C vomer V bard palate E levator Ub» maallbri* and tendon C caninu* II depreitor labU maxill.iri* 
and tendon 1 In ftaoiblut nerve L. buccinator M maxilla PM* vecond piemolir a naval trptum (cartilaRlnousl b dor 
sal conchal sinus f doTsal nasal concha <endoturWnate 1) k ventral nasal concha. (Note dorsal & sentnl scrolls.) 1 
major palatine a 2 dorsal nasal v (By Hillmarm.) _ 


ly It is extensive and forms a considerable 
part of the lateral wait of the nasal cavity It Is 
roughly pyramidal. For description, each may 
be divided into a body and four processes— 
zygomatic, frontal, alveolar, and palatine 
The facial surface of the bod) is smoothly 
concave Near the center of the bone Is the 
infraorbital foramen, the rostral opening of 
the infraorbital canal (Figs 37-37/2.' and 44) 
through which the infraorbital nerves and 
vessels emerge (Occasionally, there are two 
foramina) Located in the rostroventral part of 
the infraorbital foramen is the small alteolar 
(maxilloincisive) canal On the facial surface, 
caudal to the infraorbital foramen, is the fa 
eial crest which extends onto the zygomatic 
process and is continued as a crest across the 
zygomatic bone It is less prominent than in 
the horse Dorsal to the zygomatic crest and 
rostral to the infraorbital foramen the con 
cavity of the facial surface is referred to as the 
canine fossa Dorsally, where the maxilla 
fuses with the nasal bone, the edge is thick- 
ened and is marked by a groove at the midpoint 
for the dorsal nasal vein. 


Projecting cau dally from the ventral part of 
the body is the maxillary tuber In the imnta 
ture animal it is large and cone shaped, with 
its apex directed caudodorsally On its ventro- 
lateral surface it is marked by a distinct groove 
which is rostrally continuous with an opening 
which corresponds to the position of the last 
cheek tooth Medial to this grooie the tuber 
articulates with the perpendicular part of the 
palatine bone In the adult animal the tuber is 
greatly reduced and compressed laterally, and 
conforms to the medial wall of the pterygo- 
palatine fossa However, a narrow space re 
mains between the nail of the fossa and the 
tuber The maxillary foramen (Fig 37-35), the 
caudal opening of the infraorbital canal, is 
located just medial to the zygomatic process 
and rostrodorsal to the maxillary tuber It is 
large and oval in shape, with the edges of the 
oval directed mediolaterally On the floor of 
the foramen and continuing rostrally into the 
infraorbital canal are numerous small alveolar 
foramina At the medial edge of the maxillary 
foramen the maxilla concurs with the palatine 
and ethmoid bones in the formation of the 



37- PORCINE OSTEOLOGY 


1243 


FIGURE 37-44. Transverse sec- 
tions through nasal cavity of pig at 
level of third premolar; rostral view. 

I, frontal bone; 2, maxilla; 2’, infraor- 
bital foramen, 3, zygomatic bone; 4, ven- 
tral nasal concha (Basal lamina for at- 
tachment to conchal crest) (Note dorsal 
& ventral scrolls); I, dorsal nasal con- 
cha-black, rostral projection of endotur- 
binate 1 extending along ethmoidal crest 
of nasal bone completing the form of the 
dorsal nasal concha; white, conchal part 
of dorsal conchal sinus; PM* third pre- 
molar (level at which section was made) 
(From Hlllmann, 1971 ) 



sphenopalatine foramen (Fig. 37-41/n) and 
with the palatine bone in the formation of the 
palatine canal. 

The zygomatic process is a' short, strong pro- 
jection from the caudolateral surface of the 
body. It articulates caudaUy with the zygo- 
matic bone which overlaps it laterally. In the 
mature animal the process is excavated by the 
cavity of the maxillary sinus. 

The frontal process, directed caudodorsally 
from the body, is greatly reduced in the pig. It 
is overlapped by the lacrimal bone and con- 
curs in the formation of the osseous nasolacri- 
mal canal. 

Extending ventrolaterally from the body is 
the alveolar process. Along its ventral border 
are the sockets (ali/eo/i dentales ) for the pre- 
molar and molar teeth. At the rostral end and 
projecting slightly laterally is a large alveolus 
for the canine tooth separated from the other 
alveoli by the short interalveolar margin. Cau- 
dodorsal to the alveolus for the canine tooth is 
a projection which is variable in size, but more 
prominent in the male. 

The palatine process projects medially from 
the ventral part of the body adjacent to the 
alveolar process. Together with its fellow of 
the opposite side with which it fuses, it forms 
the major portion of the hard palate. It is very 
Jong Caudally it is smooth. At its most caudal 
extent it presents the elongate major palatine 
foramen, the rostml opening of the major pala- 
tine canal. Continuing rostrally from this fora- 
men, the entire process is marked by a longi- 
tudinal groove Caudally the groove parallels 
closely the palatine process, but at the level of 
the second premolar tooth deviates medially. 
Approximately from this point rostrally the 
Pcocrvs K marked by 10 to 12 transverse 
Krcx>vet and ridges corresponding with those 
of th v mucous membrane of tire hard palate 


( impressiones rugales). The mediorostral ex- 
tent of the palatine process concurs with the 
incisive bone to form the palatine Assure. 

In the immature animal the nasal surface of 
the body and palatine process is lqngitudinally 
concave. It is interrupted in its caudodorsal 
part by the maxillary hiatus* leading into a dis- 
tinct lateral excavation, the maxillary sinus. 
The sinus is dorsal to the infteiorbital canal 
and extends into the zygomatic process. Ex- 
tending rostroventrad from a point dorsal to 
the maxillary hiatus is the crest for the ventral 
nasal concha (nasal crest). 

The iNFRAonniTAL canal. The infraorbital 
canal extends longitudinally in a rostral direc- 
tion from the maxillary foramen to the infra- 
orbital foramen. The canal is wide and is com- 
pressed dorsoventrally and, for the most part, 
its roof serves as the floor of the maxillary si- 
nus. Its floor, formed by the alveoli of the 
molar teeth, is irregular and perforated by 
numerous foramina. It gives passage to the 
infraorbital vessels and nerves. 


NASAl BONES 

The nasal hone (Figs. 37-34/B, 41/B and 
42/1) is paired. It is long, and forms the dor- 
sum of the nose and, internally, a considerable 
part of the roof of the nasal cavity. It presents 
external (dorsal), internal, medial and lateral 
surfaces. Laterally, it articulates with the in- 
cisive and maxilla, caudally with the frontal 
and first endoturhinatc of the ethmoid and 
mediall) with its fellow of the opposite side. 
Approximately the rostral one fifth of the 
paired bones Is free and extends between the 
laterally curved naval cartilages 


*TtM» f-iixJlarr 1-Utu* u I'w.erotlrtf Inth* imr-atur* jve 


1244 

The external (dorsal) surface is flattened, 
with the exception of the Bupraorbital sulcus, 
which crosses the caudolateral surface in an 
oblique manner Caudally it is marked by 
transverse, undulating grooves for a venous 
plexus between the right and left dorsal nasal 
veins The lateral borders gradually taper ros 
trally At the rostral limit of the articulation 
with the incisive, it concurs in the formation 
of the large nasomaxillary notch (Fig 37-34/2) 

The lateral surface is flat, caudally it is wide 
and smooth where it articulates with the max- 
illa, rostrally it is rough and articulates with 
the incisive 

The medial surface is flat and rough and 
articulates with the bone of the opposite side 
The internal (nasal) surface presents a cen 
tral crest, the ethmoid crest, extending from 
the nasomaxillary notch in a caudal direction 
Caudally, in the articulated skeleton, the crest 
is strengthened by the rostral continuation of 
endoturbinate I On the medial face of the 
ethmoid crest there is a deep groove that car 
n's the ethmoidal nerve As it reaches the 
rostxoventral border of the crest it penetrates 
the bone and is continue 1 on the lateral sur 
face of the snout Medial to the crest, the in 
temal surface is deeply g-ooved, conforming 
to the dorsal nasal meatus, lateral to the crest, 
it is grooved conforming to the middle nasal 
meatus Caudally, the nasal bone is variably 
excavated laterally along the course of the 
ethmoid crest, resulting in the formation of 
the dorsal conchal sinus In the unmature 
animal the excavation extends rostrally to the 
level of the second premolar, accounting for 
about half the length of the bone The extent 
of the excavation vanes considerably dorso- 
ventrally and latetomedially (occasionally 
reaching the midline) However, the sinuses 
of the nght and left sides remain independent 
Caudomedially, the bone is excavated in a 
variable manner and extent by the frontal 


INCISIVE BONE 

The incisive bone (Figs 37-34, 35,41 and 
42) is paired and forms the most rostral extent 
(wnth the exception of the os rostrale) of the 
bony skull The disarticulated bone presents a 
body and three processes -alveolar, nasal and 
palatine It articulates with the nasal and 
maxillary bones and indirectly with the os 
rostrale The fusion of the paired bones along 
the midline is incomplete, therefore, forming 
the narrow mtermcisive fissure (Fig 37- 
35/5) In the articulated skull the incisive 
bone concurs in the formation of the hard 
palate and the bony nasal aperture (aperture 
nasi ossea) 

The body is elongate, thickened rostrally 
and tapered caudally, and presents labial and 


PORCINF 

palatine surfaces Latcrocaudad to the body Is 
the palatine surface It is narrow, forms the 
lateral border of the palatine fissure and is 
marked by two to three transv erse groov cs ana 
ndges which correspond to the distinct rugae 
of the hard palate It is continuous with the 
palatine process of the maxilla. Rostromedi- 
ally, It is concave and marked by the rostnu 
continuation of the palatine sulcus lateral to 
the palatine fissure From here the sulcus 
curves sharply medlad, paralleling the alve- 
olar process, and courses on the medial sur- 
face of the body either as n groove or, occa- 
sionally, as a canal (the formation may be 
variable between right and left sides) It trans- 
mits the palatolabial artery 
The alveolar process extends ventrolateral 
ly from the body and Is much reduced It con- 
tains the three upper incisor teeth in its soc)^ 
ets (a/ueoli dentalcs) along the smooth 
alveolar arch 

The nasal process extends from the body in 
a dorsocaudal direction. It Is broad and thin, 
and forms the rostral part of the lateral nasal 
wall It presents two curved surfaces— the 
lateral or external face which is convex and 
smooth, and the internal or nasal face which 
is doubly concave with a sharp crest separa 
ting the concavities This crest is continuous 
caudally with the conchal crest of the maxilla. 
Dorsomedially, the nasal process articulates 
with the nasal bone Together with the rostral 
projection of the nasal bone the incisive com- 
pletes the nasoincislve notch ( inctsura naJO- 
maxtl/am) (Fig 37-34/2) The rostral or 
leading edge of the nasal process forms a sharp 
ridge which blends with and accepts the nasal 
cartilages 

The palatine process is a thin medial plate 
of bone which projects caudally from the 
body to articulate with the maxilla. In the 
adult, it extends to a transverse plane, passing 
rostral to the first premolar Medially, it is 
fused with the bone of the opposite side, Jat 
erally, it fuses with the palatine process of the 
the Palatine fissure (Fig 
0/-35/8) The lateral, unfused wall of the pala 
tine process contains a shallow groove which 
receives the cartilage of the vomeronasal 
organ When the nght and left palatine proc 
esses are fused on the midline a median V- 
stiaped groove ( sulcus septi nasi) is present 
vhich accepts caudally the rostral extension 
of the vomer and rostrally the nasal septal 


.PAIATINE BONES 

(Figs 37-35/E and 41 /D) 

The palatine bones are situated on either 
side of the choanae (caudal nares), and form 
the caudal part of the hard palate Each articu- 
lates with the bone of the opposite side, the 
maxilla, pterygoid, basisphenoid vomer, pre- 



37— PORCINE OSTEOLOGY 


1245 


sphenoid and ethmoid Each is twisted so as to 
form a horizontal and a perpendicular plate 
The horizontal plates, when fused on the 
midline, form approximately the caudal one 
fifth of the hard palate The palatine surface 
is triangular, with the base caudal and the 
apex rostral, interposed between the palatine 
processes of the maxillae It is smooth, with 
the exception of an oblique transverse ndge 
that occurs as the palatine crest Lateral to the 
crest and on the line of the palatomaxillary 
suture several foramina, the minor palatine 
foramina, are present, rostral to which is the 
major palatine foramen, the rostral opemng of 
the major palatine canal The nasal surface is 
deeply hollowed and has a medial nasal crest 
which extends dorsally and articulates with 
the vomer Thus, the two bones form a com 
plete bony septum m the caudal part of the 
nasopharynx, separating it mto right and left 
halves Caudally it is notched and generally 
presents a caudally projecting spine 
The perpendicular plate is slightly concave 
on its nasal surface, smooth and quite thin as 
it forms the lateral wall of the nasopharynx It 
is roughly triangular Rostrodorsally, it is 
notched by the sphenopalatine incisure which 
concurs with the maxilla and ethmoid to 
complete the sphenopalatine foramen Lead 
mg ventral to the sphenopalatine notch and on 
the lateral surface, the perpendicular plate is 
grooved to form the medial wall of the major 
palatine canal. The canal is completed by a 
corresponding groove on the medial surface 
of the maxilla Leading caudal to the spheno 
palatine notch on the nasal surface is a thin, 
elongate horizontal plate of bone (the lamina 
sphenoethmoidalis), which is contmuous 
caudally with the presphenoid bone and me 
dially with the vomer forming the roof of the 
nasopharyngeal meatus Between this lamina 
and the most lateral projecting perpendicular 
part (which articulates with the orbital plate 
of the ethmoid) there is a distinct depression 
which forms part of the floor of the fundus of 
the nasal cavity This depression is continuous 
caudally with the sphenoid sinus and rostrally 
leads over the basal lamina to communicate 
with the nasal cavity Ven trolly, the lateral or 
maxillary surface of the perpendicular plate is 
marked by an area of fusion with the maxilla. 
Caudoventral to this, the perpendicular plate 
presents a blunt, thick, rounded pyramidal 
process Caudally, the process articulates with 
the pterygoid process of the basisphenoid bone 
and the pterygoid bone 


pterygoid BONES 
(Tigs 37-35/C and 41/E) 

The pterygoid bones are paired Each is 
early \erti cal j n direction and is narrow In 
e ai w *de at eacli end It articulates 
h the palatine bone ptcry gold process of 


the basisphenoid, and the vomer The lateral 
surface is free ventrally and forms the medial 
wall of the pterygopalatine fossa The ventral 
edge is notched for the course of the tendon of 
the tensor veil palatini, caudal to the notch is 
the thin, blunt hamulus Its medial face is 
smooth and forms the caudal limit of the 
bony nasopharyngeal meatus 

LACRIMAL BONES 

(Figs 37-34/f and 42/E) 

The lacrimal bone is located in the rostral 
margin of the osseous orbit It is irregular in 
shape and articulates with the maxilla, zygo 
malic, ethmoid, frontal and, toa limited extent, 
the nasal and ventral conchal bones 

Its orbital face is concave to allow for the 
presence of the deep gland of the third eyelid 
(Hardenan gland) and the orbital venous si 
nus Deep within the concavity is a deep fossa 
for the origin of the obliquus ventralis muscle 
Lateral to these depressions is a crest which 
is continuous with the periorbita This crest is 
interrupted by an oblique groove which re 
ceives the malar artery as it courses dorsally 

The facial surface is concave and also pre 
sents a crest which is continuous ventrally 
with the facial crest of the zygomatic and 
maxillary bones, as it outlines the fossa of the 
levator labn maxillans Immediately caudal to 
this crest (occasionally occurring within the 
crest) are the paired lacrimal foramina directed 
dorsally and laterally, respectively, which be 
come confluent and lead m a rostromedial di 
rection into the lacnmal canal 

The nasal surface is very complicated It is 
marked by a distinct ndge, lateral to which is 
the excavation for the maxillary sinus The 
maxillary sinus in the immature specimen 
possesses a caudal extension, the lacrimal 
bulla, which is very thin walled and small 
Caudomedial to the ndge, the surface is 
marked by a senes of minor excavations (po 
tential compartments of the paranasal si- 
nuses) separated by ndges corresponding to 
the lamina of the ethmoid bone In the mature 
animal the lacnmal bone is vanably excavated 
to form a lacnmal sinus Dorsomedial to the 
ndge the internal surface is marked by a flat- 
tened, curved groove which represents the 
lateral wall of the nasomaxillary opening 

Lacnmal Canal 

The bony lacnmal canal is located within the 
lacnmal bone coursing in a rostromedial direc- 
tion It is continuous caudally with the paired 
lacnmal foramina in the orbital ndge of the 
lacnmal bone It is continued rostrally by a 
bony tubular extension which fits into a deep 
groove formed In the caudodorsal portion of 
the ventral nasal conchal bone The groove is 
completed b> the nasal surface of the maxilla 



1246 

immediately ventral to the conchal crest 
forming the lateral wall of the nasolacrimal 
canal ’The nasolacrimal canal does not extend 
beyond the level of the fourth piemolar tooth 
in the immature specimen or the level of the 

first molar tooth in the mature specimen The 
nasolacrimal duct, which lies within the naso- 
lacrimal canal, does not always empty or ter 
mrnate in the ventral conchal sinus Occa 
stonaUy, a rostral remnant may be found in 
some specimens 

ZYGOMATIC BONES 

(Figs 37-34/D, 35/D and 42/F) 

The zygomatic bone is wide dorsoventrally 
and compressed mediolaterahy Its lateral 
surface is broad and slightly convex, and los 
trally concurs with the maxilla and lacrimal 
bones in the formation of the muscular fossa. 
The fossa is limited by the facial crest 
The orbital face is small and deeply grooved 
It concurs in the formation of the bony orbit 
Caudal to the orbital surface and projecting 
dorsally is a smaU sharp frontal process 
Ven trally projecting in a caudal and slightly 
dorsal direction is the large, pointed temporal 
process Its dorsal border, together with the 
caudal border of the frontal process, forms » 
notch which receives the zygomatic process 
of the temporal bone, completing the strong 
zygomatic arch. Its ventral border is free, 
convex and tapers caudally 
Rostromedially, the zygomatic boneisexca 
vated by the maxillary sinus 

VENTRAL NASAL CONCHAL 
BONE 

(Fig 37-40/4) 


The ventral nasal conchal bone (maxtilo 
turbinate bone) (Figs 37-4 1/M and 44/4) oc 
cupies the major portion of the nasal cavity 
and is more complex than the dorsal nasal 
concha. It arises from a separate center of 
ossification and is easily removed in the dis 
articulated, immature skull Eventually, it 
fuses with the maxilla, lacnmal and ethmoid 
bones It Is composed of a basal lamina (at 
tached to the conchal crest of the maxilla) 
which is divided at its medial edge into sec 
ondary laminae, forming a dorsal and ventral 
part The basal lamina extends longitudinally 
along the course of the ventral conchal bone, 
its rostral two thirds being oriented in a hon 
zontal plane while the caudal one third is in a 
vertical plane 


PORCINE 

Arising In a dorsal direction from the medl 
al edge and at right angles to the basal lamina 
is the dorsal part (Fig 37-41/m) It consists of 
one and one half lateral turns forming a scroll 
throughout its entire length Rostrally, it Is 
open, caudally, it ends in a closed spiral ert 
closing a recess of the nasal cavity 
The ventral part Is more complex than the 
dorsal (varying with age and specimen) In 
the mature specimen, the rostral part (approx 
imately three quarters) consists of a second 
ary lamina which scrolls one to one and one 
half times toward the ventral lateral wall 
(Fig 37-41 fm) The recess (of the nasal 
cavity) formed by the scroll is further sub- 
divided into separate cells by small, incom 
plcte transverse septa. The caudal part or 
approximately one quarter, the ventral con- 
cha! sinus (Fig 37-41/m'), Is separated from 
the rostral pan by an irregular transverse 
septum The sinus is in free communication 
with the recess of the rostral pan through a 
dorsal opening (variable in size) in the trans 
verse septum at a level between the premolar 
and molar teeth Opening into the ventral 
conchal sinus from a caudodorsal direction 
in the mature animal is the nasolacrimal 
canal • In the immature specimen, the caudal 
surface of the ventral nasal conchal bone con 
sists of a triangular plate of bone, deeply 
concave, thin and papyraceous When articu 
lated, this caudal surface conforms to the 
maxillary hiatus, and thus forms the rostro* 
medial wall of the maxillary sinus The caudo- 
medial edge of the thin triangular bone 
articulates with the orbital plate of the eth 
moid bone, thus completing the medial wall 
of the maxillary sinus Immediately rostral to 
the caudomedlal edge is a shallow groove 
which carries the vessels and nerves to the 
maxillary sinus and laterodorsal nasal cavity 
Occasionally, the dorsal portion of this groove 
bridges over in the mature specimen, forming 
a very short canal for the vessels and nerves 


MANDIBLE 

(Figs 37-33, 42 and 45) 

The mandible, or lower jaw bone, is the 
largest bone of the face At birth it consists 
of two halves, which unite soon after, and it is 
usually described as a single bone It carries 
the lower teeth, and articulates by ns condylar 
process with the squamous part of the tem 
poral bone on either side It consists of a body 
and two vertical rami 

The bodies are joined at the symphysis and 


"The lacnmal canal Is found in the lacrimal bone only 
however with osseous extensions into the maxilla and 
ventral nasal conchal bones the entire osseous canal l* 
referred to as the nasolacrimal canal 


•In- the unmacerated skull the mucous membrane lining 
which forms the nasolacrimal duct, fail* vcftpvt Wto the 
sinus but continues rostrally beneath the basal lamina 
emptying into the ventral nasal meatus 



37- PORCINE OSTEOLOGY 


1247 



A, Incisive part and B, molar part of body, B\ ramus. C, 
condylar process, D, coronold process, 1. 2, 3. Incisor 
teeth; 4, canine tooth. 5, 6. 7. premolar teeth (first absent), 
8, 0, 10. molar teeth 


diverge at a greater angle than in the horse 
or ox. Each narrows decidedly rostraUy The 
mental surface slopes ventrally and caudally 
and forms a distinct prominence at the point 
of divergence. Internally, dorsal to the angle 
formed by the two bodies is a pair of medial 
mental foramina. On the labial surface there 
are lateral mental foramina. The alveolar 
border of the incisive part presents six alveoli 
for the incisor teeth, and a little further 
enudad tv, o large cavities for the canine teeth. 
The molar part is very thick and strong. Us 
lateral surface is convex dorsoventrally. The 
medial surface is prominent over the roots of 
the molar teeth and overhangs the concave 
\enlrnl part. The alveolar border Is thin ros- 
trallj and widens caudally, parallel with that 
of the opposite side. There are seven alveoli 
for the lower check teeth which increase 
In %\ 2 c rostrocaudally. The first is small and is 
not always present in the adult; it is separated 
by short spaces, interalveolar borders, from 
the second and the canine alveolus 
The rsmu# is the vertical part which is 
expanded and furnishes attachment to pow cr- 


ful muscles. The lateral surface is roughly 
flattened, with the exception of the dorsal 
half, which is concave for the masseteric 
fossa. The medial surface is flattened and, 
near its middle, is marked by the presence of 
the mandibular foramen, the caudal opening 
to the mandibular canal. The mandibular 
angle is smoothly curved, is thick caudally, 
and presents medial and lateral ridges outlin- 
ing it. The ridges present secondary trans- 
verse ridges for muscular attachment. The 
coronoid process continues the ramus dor- 
sallv. It is small and thin edged, and is separ- 
ated from the condylar process by a wide 
notch, the mandibular incisure. The condylar 
process extends from the ramus dorsally in 
a caudal direction. It is convex in both direc- 
tions, is wide rostraUy and is narrow and 
declivitous caudally. 

HYOID BONE 

(Fig. 37-46) 

The basihyoid is broad rostrocaudaUy and 
short transversely, and bears on its ventral 
aspect a very short, pointed lingual process. 
The thyrohyoids are wide and curved, concave 
and grooved dorsally; their ends are attached 
to the thyroid cartilage of the larynx by rather 
long bars of cartilage. The ceratohyoids are 
short, wide, and flattened dorsoventrally; 
they are attached to short bars which pro- 
ject from the junction of the basihyoid and 
thyrohyoids. The epihyoid is a little longer 
than the ceratohyoid, but is relatively slender; 
it is largely cartilaginous in the young subject 
and does not ossify at either end, The st>lo- 
hyoid is a very slender rod, slightly enlarged 
at either end; the dorsal extremity is attached 
to the styloid process of the temporal bone by 
a rather long and wide bar of cartilage, the 
tympanohyoid. 



f ir.mtE 37-46. Hyoid Lone of pjj;. OMlroliIrral 
view. 

l.Tyro^nofiyoltl. 2. *t>lo)j>old, 3, vplhvoM. 4. crrMo- 
hroM. s. thrrp*irotd r„ of 5 7, luvihroid (trsdrf 

on*' tc—v orrr lincyal 



1248 


PORCINE 



FIGURE 37-47 Nasal cartilages 
and rostral bone of pig. lateral view 

A Incisive bone B nasal bone C ros 
tral bone 1 dorsal lateral nasal cartilagd 
(caudal part) and I rostral part 2 ven 
tral lateral nasal cartilage 3 lateral ac- 
cessory nasal cartilage 4 lateral a per 
ture for exit of dorsal nasal v I, and I* 
first and third Incisors Dotted line indi 
cates the position of the rostral bone as It 
occurs within the nasal cartilages (From 
Hillmann, 1971 ) 


KOSTRAl BONE (os rosfrafe) 
(Figs 37-47, 48 and 49) 


The rostral hone is located in the most 
rostral extern of the nasal septal cartilage It is 
formed from two centers of ossification and 
fuses early lacking specific shape Thisossifi 
cation Is similar to that occumng In the 
caudal part of the nasal septum resulting 
in the osseous nasal septum 
In the mature animal the bone is pyramidal 
in appearance with its base directed rostro- 
ventrad and its apex directed into the cartila 
gtnous nasal septum The base Is slightly 
convex and marked by a median fissure (Figs 
37-48 and 49/5) Dorsally the base deviates 
laterally forming two rounded columns 
which are continuous with the dorsal lateral 
nasal cartilages Ventrocaudahy, the baser 


also splits forming two, paired, secondary 
projections— ventromedial and dorsolateral 
to each other The ventromedial pair extends 
directly toward the incisive bone and, in the 
unmacerated state, is bound to it by strong 
connective tissue The dorsolateral pair 
curves laterally and forms a base for the 
lateral accessory nasal cartilage On the mid 
line approximately in the center of the basal 
surface, is a foramen which receives a um 
lateral branch of the continuation of the major 
palatine artery serving as the nutrient artery 
for the rostral bone 

The lateral face of the rostral bone is 
smooth and concave, and forms the medial 
wall of the nostrils it blends smoothly with 
the basal surface 

Centrally on the dorsal surface is a deep 
fissure which is continuous with the basal 
fissure 



FIGURE 37-48 Nasal cartilage* 
and rostral bone of pig dorsal view 


tral bone 1 dorsal lateral nasal cartilage 
(caudal part) and 1 rostral part 2 ven 
tral lateral nasal cartilage 3 lateral ac 
cessory nasal cartilage 4 lateral a per 
lure for exit of dorsal nasal v 5 median 
fissure (illustrating rostra] fusion) Dot 
ted line indicates the position of the 
rostral bone as it occurs within the nasal 
cartilages (From Hillmann 1971 ) 



37- PORCINE OSTEOLOGY 


1249 


FIGURE 37-49 Nasal cartilages 
and rostral bone of pig, v entral ' lew . 

A incisive bone, C, rostral bone, 1 , 
dorsal lateral nasal cartilage (rostral 
part) 2. i entral lateral nasal cartilage. 3 
lateral accessory nasal cartilage 5, me- 
dian fissure, 6 incisive papilla, 7, inci 
sive duct. 8. palatine rugae. 1, and It 
first and second incisors Dotted line In 
dtcates the position of the rostral bone as 
It occurs within the nasal cartilages 
(From Hillmann 1971 ) 



SKULL AS A WHOLE 

(Fig 37-42) 

The length and profile vary greatly in differ- 
ent breeds Primitively, the skull is long— 
especially in its facial part— and the frontal 
profile is almost straight The condition is 
very pronounced m wild or semi feral pigs, 
and exists also— although in less degree— m 
the improved breeds during extreme youth 
Most of the latter are decidedly brachy- 
cephalic when fully developed, the face is 
“dished” in a pronounced fashion The frontal 
region is flattened, slopes rostrally and lacks 
the external sagittal crest caudally The nasal 
region is shortened, and in some specimens 
even distinctly concave in profile The supra 
orbital foramina are about midway between 
the orbital margin and the frontal suture The 
supraorbital grooves extend rostrad from the 
foramina to the nasal region and turn ventro 
laterally onto the maxilla for a short distance 
The lateral surface is triangular when the 
mandible is included The temporal fossa is 
entirely lateral, and its long axis is almost 
vertical It is bounded dorsocaudally by the 
nuchal crest, caudally by the temporal crest 
and rostrodor sally by the temporal line, and 
is marked off from the orbital cavity by the 
zygomatic process and a curved crest which 
extends from it to the root of the pterygoid 
process The zygomatic arch is strong and 
high, is flattened from side to side, and is 
short rostrocaudally Its root is notched dor- 
sally and bears a projecuon ventrally Ros 
trally, it curves sharply dorsally and forms a 
pointed, recurved projection dorsal and rostral 
to the external acoustic meatus The orbit is 


small Its margin is deficient caudolaterally 
m the dry skull, thick caudolaterally and 
rounded rostrally and ventrally. The cavity is 
limited ventrally by a ndge on the frontal and 
lacnmal bones, and is separated by a crest 
from the temporal fossa The medial wall is 
perforated dorsally by the orbital opening of 
the supraorbital qanal, and ventrally by the 
optic and ethmoidal foramina, on its rostro 
ventral part is the fossa in which the obliquus 
ventralis muscle of the eye takes ongin Two 
lacnmal foramina are found on or close to the 
rostral margin The pterygopalatine fossa is 
well defined, its dorsal part forms a deep 
groove which leads from the foramen orbito- 
rotundum to the very large maxillary foramen 
The lateral nasal region is deeply grooved in 
its length and is clearly marked off by a ndge 
from the dorsal nasal and frontal regions The 
facial crest is short and usually sharp edged, 
and lies dorsal to the fifth and sixth cheek 
teeth Slightly (ca 2 cm) rostral to it is the 
infraorbital foramen There is a ndged promi- 
nence over the canine alveolus In some skulls 
the rostral part of the upper jaw is inclined 
dorsally 

The most stnking features of the basal 
surface (Fig 37-35) are as follows The basal 
part of the occipital bone is flattened, it bears 
a median crest, the pharyngeal tubercle, and 
two lateral muscular tubercles The jugular 
process is extremely long, less flattened than 
in the horse and ox, and nearly -vertical At 
the medial side of its root is the canal for the 
hypoglossal nerve and rostrolateral to the root 
are the stylomastoid foramen and a deep 
cavity in which the styloid process is con- 
cealed The tympanic bulla is long, com- 



1250 


PORCINE 


pressed laterally and bears a sharp short, 
muscular process Caudal to the tympamc 
bulla and medial to the jugular process is t*j e 
jugular foramen Continuous and shghtly 
rostral to the latter and medial to the tym 
panic bulla is the petrooccipital fissure The 
fissure widens rostromedially to become the 
foramen lacerum Rostral to the tympanic 
bulla is the spinous incisure rostromedial 
to this is the oval incisure and further rostro 
medially is the carotid mciSure The choanae 
are small and are wider ventrally than dor 
sally The most ventral part is the tuberosity 
of the palatine bone caudodorsal to which is 
the pterygoid fossa The palate constitutes 
about two thirds of the entire length of the 
skull and is relatively narrow It is widest 
between the canines and premolars and nar 
row at each end It is marked by a crest medi 
ally and by the major palatine foramen caudo 
laterally, caudal to it are the minor palatire 
foramina and the major palatine groove later 
ally Rostrally toward the apex are the large 
paired palatine fissures Th* rostral pan 
bears transverse ndges It is moderately 
arched from side to side In some specimens 
it is nearly straight or slightly concave in its 
length in others it curves dorsally to a van 
able degree rostrally The caudal end alwavs 
slopes dorsally, more or less 
The nuchal surface (Fig 37-33) is remark 
able for its height and the breadth of the 
nuchal crest The central part dorsal to the 
foramen magnum is smooth and concave 
from side to side, and is bounded laterally by 
ridges which conv erge ventrally and end on 
two nuchal tubercles at the dorsal margin 
of the foramen magnum The surface is 
separated from the temporal fossae by the 
temporal crests, which curve ventrorostro- 
laterally to blend with the external acoustic 
meatus The mastoid process is greatly re 
duced and has the form of a plate which over 
laps the root of the jugular process The mas 
toid foramen is absent 
The cranial cavity (Fig 37-41) is small, 
in spile of the great sire of the cranium the 
discrepancy is due to the enormous develop- 
ment of the frontal sinuses in the adult It is 
relatively longer, but much lower than that 
of the ox Its width is greatly diminished be 
tween the orbits The floor of the cranial 
cavity is divided into three cranial fossae 
The rostral cranial fossa presents the optic 
canal and is considerably elevated when com 
pared to the middle and caudal fossae The 
ethmoidal fossae extend rostrocaudally, with 
their widest part slightly rostral to their 
middle In the caudolateral wall of the eth 
moidal fossae is the ethmoidal foramen- The 
middle cranial fossa js deep and presents the 
median sella turcica which in some speci 
mens is completed lateral!} by the presence 
of the fused rostral and caudal chnoid pro 


cesses and the more caudal dorsum sellae 
Lateral and slightly caudal to the sella turcica 
is the foramen lacerum. Lateral to this, the 
middle cranial fossa is longitudinally grooved 
for the course of the fifth cranial nerve Caud 
ally, this groove is continuous externally with 
the oval incisure Dorsal to the groove is a 
sharp ndge which is continued caudally with 
the tentorial crest and rostrally with the pre 
sphenoid bone, forming a distinct shelf over 
lying the foramen orbitorotundum More 
laterally, the middle cranial fossa presents 
a distinct vascular groove for the course 
of the middle meningeal artery The caudal 
cranial fossa is expanded in its rostral part 
and narrows caudally into the foramen mag 
num The floor is smooth and rostrolaterally 
becomes the petrooccipital fissure, which is 
continuous rostrally with the foramen lacerum 
and caudolaterally with the jugular foramen. 
Caudomedial to the jugular foramen, pene 
tratmg the floor of the caudal cranial fossa, is 
the internal opening of the canal for the hypo 
glossal nerve Dorsolaterally, delimiting the 
caudal cranial fossa from the middle, is the 
tentorial crest, which is reduced caudally 
Ventral to the crest there occurs a major part 
of the lateral wall for the petrous part of the 
temporal bone The internal occipital pro- 
tuberance is reduced and the temporal meatus 
is absent 

The nasal cav ity is very long Its caudal part 
is divided by the basal (transverse) lamina 
into olfactory and respiratory parts The ol 
factory part or fundus is dorsal, and contains 
the ethmoturbmates and ethmoidal meatuses 
The ventral pan is continuous rostrally with 
the ventral nasal meatus and leads caudally to 
the pharyngeal onfice, hence it is called the 
nasopharyngeal meatus The bony roof is al 
most complete rostrally on account of the great 
length of the nasal bones Occupying the dor 
solateral part of the nasal cavity is the elon 
gate dorsal nasal concha. It is composed of the 
conchal crest of the nasal bone rostrally and 
endoturbinate I caudally Ventral to the shelf 
of the dorsal nasal concha in the lateral part 
of the wall is the nasofrontal aperture, which 
extends dorsally, and the nasomaxillary aper- 
ture, extending laterally Ventral to the dorsal 
nasal concha, and occupying the major part 
of the nasal cavity, is the ventral nasal concha, 
which is broad and flat caudally and tapered 
rostrally 

Paranasal Sinuses 

MAXILLARY SINUS 

(Figs 37-3G/H and 37) 

The maxillary smug, present at birth, is 
located mainly within the maxilla, and to a 
variable extent in the zygomatic, lacrimal, 
ethmoid and ventral concha! bones In the 



37— PORCINE OSTEOLOGY 


1251 


mature animal, it is a well developed sinus 
and presents medial, lateral and dorsocaudal 
extensions A broad, low ridge or septum 
(corresponding to the course of the infra- 
orbital canal) projects from the osseous floor 
and incompletely divides the sinus into the 
medial and lateral extensions (Figs 37-36 
and 37/H) CaudaUy, dorsal to the level of 
the maxillary foramen, the septum is van 
ably excavated by the presence of an ethmoi- 
dal cell, tnangular in cross section (Figs 
37-36 and 37/1) The floor of the medial 
extension is higher than that of the lateral 
The dorsocaudal extension excavates into 
the lacnmal and zygomatic bones The 
lacnmal canal courses within the roof of the 
sinus, separated from it by a thin, bony 
plate (Fig 37-37/6) Medially and slightly 
rostrally, at the junction of the medial and 
dorsal walls of the sinus, is the laterally com 
pressed nasomaxillary opening. The floor of 
the maxillary sinus usually does not extend 
more than 1 cm ventral to the level of the 
facial crest Rostrally, the sinus ends about 
1 to 2 cm caudal to the infraorbital foramen 
or in a transverse plane through the first 
molar tooth Caudally, the maxillary sinus 
extends to a transverse level passing through 
the last molar tooth 

In one half of the specimens examined by Hillmann 
(1971) a thin walled bony bulla was found ventral and 
medial to the nasomaxillary opening and connected with 
an ethmoidal meatus either directly or through a rostral 
frontal sinus 

Nasomaxillaiiy aperture The naso- 
maxillary opening (aperture) (Figs 37-41/4 
and 44/H) serves to connect the nasal cavity 
with the maxillary sinus It is an elongate, 
laterally compressed passageway It is formed 
by the dorsal nasal surface of the maxilla, the 
ventral nasal concha! bone, the nasal surface 
of th6 lacnmal bone, and the dorsolateral sur 
face of the orbital plate of the ethmoid bone 
It begins m the middle nasal meatus at the 
level of a transverse plane through the first 
molar tooth Here, the first endoturbinate 
lies dorsomedially and the ventral nasal 
concha ventrally From here, it courses 
slightly laterad and dorsad to finally empty 
into the medial dorsal wall of the maxillary 
sinus at a level of a transverse plane through 
the last molar tooth 


FRONTAL SINUSES 

(Figs 37-36 and 37/ A, B,C, 

40 and 4l/f and g) 

The frontal sinuses represent the greatest 
excavation and are the most complex of all 
the paranasal sinuses Developmentally, they 
are separable into two entities, the rostral 
and caudal frontal sinuses Tne caudal frontal 
sinus dev elops and retains a direct connection 
with the nasal cavity, clmilar to the maxillary 


sinus, whereas the rostral frontal sinuses 
clearly communicate through the ethmoidal 
meatuses Therefore, two separate systems 
exist Considerable variation exists between 
specimens and should be taken into con- 
sideration 


Caudal Frontal Sinus 

The caudal frontal sinus (Figs 37-36, 37 
and 38/B, 40/A and 41/F,F ) in the mature pig 
usually represents the largest of the paranasal 
sinuses and excavates the frontal, parietal, 
occipital and, to a variable extent, the tem 
poral bones 

Developmentally, the caudal frontal sinus 
is usually the first to show any appreciable 
excavation into the frontal bone In the young 
specimen^ the floor of the sinus, depending 
upon the extent of excavation, represents 
the basal lamina from which the first endo- 
turbinate develops Thus, the caudal frontal 
sinus (and similarly the medial and lateral 
rostral frontal and lacnmal sinuses and the 
ethmoidal cells) establishes a relationship 
with the nasal cavity via the ethmoidal 
meatuses 

In some instances the excavation may be limited re 
suitiuc-Jn a diminutive caudal frontal sinus (Fig 37- 
38/B) In this case the rostral frontal sinusrt lire more ex 
tensive than usual taking mcr the area usually occupied 
by the caudal frontal sinus 

Normally, the sinuses of the nght and left 
sides are separated by a median septum, 
which occasionally deviates unilaterally (the 
septum sinuum frontalium) In the mature 
specimen, the caudal frontal sinus is usually 
extensively excavated, resulting in a thin 
outer and inner lamellae of bone This hoi 
lowed structure is greatly strengthened by 
numerous incomplete bony lamellae, lamellae 
mtrasinuales, forming compartments which 
freely communicate with each other, but not 
with those of the opposite side 

Nasofrontal opening (Fig 37-41/2) In 
the mature specimen the nasofrontal opening, 
approximately 3 cm in length, occurs at the 
level of the last molar tooth It is compressed 
laterally as a result oi the increase in size 
of the neighboring frontal sinuses and, on 
Occasion, the mucous lining of the medial 
and lateral walls may be in contact with each 
other 

Medial Rostral Frontal Sinus 

The medial rostral frontal sinus (Figs 37- 
36, 37 and 38/A and 41/g) is the next lateral 
ethmoidal compartment to the caudal frontal 
sinus Its formation is different from that of 
the caudal frontal sinus m that it is bounded 
by two basal ethmoidal laminae fused with 
two corresponding laminae of the frontal 
bone (Fig 37-36/A) It develops medially 



1252 


PORCINE 


compressing the nasofrontal aperture It is 
located in the rostral part of the frontal bone 
the right and left halves remaining separate 
Occasionally, the medial rostral frcntal sinus 
communicates directly with the dorsal 
conchal smus and with the nasal cavity 
Sometimes it extends rostrally into the nasal 
bones and c3udally to the level of the medial 
wall of the orbit 


lateral Rostral Frontal Smus 
The lateral rostral frontal sinus (Figs 37- 
36, 37 and 38/C) is a relatively large para 
nasal smus in the mature animal only It 
develops independently of the neighboring 
frontal sinuses It is caudolateral to the medial 
rostral frontal sinus, extending into the 
medial wall of the orbit and excavating the 
processes of the frontal bone 


LACRIMAL SINUS 

The lacrimal sinus (Figs 37-36 and 37/G) 
develops variably and can be defined as the 
excavation into the lacnmal bone by the 
fourth or fifth ethmoidal meatus It may be 
greatly reduced or absent or it may occur as a 
part of the development of the rostral frontal 
smuses It is bordered vcntrolaterally by the 
lacnmal canal and the maxillary smus 
medially and dorsally by the rostral frontal 
sinuses and caudally by the rostromedial 
wall of the orbit 


SPHENOID SINUS 

The sphenoid smus (Figs 37-38, 39 and 
40/D and 41/h) is more complex in the pig 
than in the other domestic animals It is 
paired, the right and left sinuses being sepa 
rated by a septum, septum sinuum sphenoid- 
altum Complete growth of the sinus results 
In the excavation of the presphenoid, basi 
sphenoid and temporal bones, and it is in 
close proximity to the optic chiasma. It com 
mumcates caudally with the fundus of the 
nasal cavity via the ventral ethmoidal 
meatuses The smus presents three exten 
sions One is rostral into the pterygoid process 
of the basisphenoid occasionally reaching 
the palatine bone Another extensively ex 
cavates laterally and dorsally into the squa 
mous part of the temporal bone, reaching into 
the zygomatic process There is also a caudal 
extension Into the basal part of the occipital 
bone 


ETHMOIDAL CELLS 

The ethmoidal cells (paraethmoidal smuses 
of Loeffler, 1959) (Figs 37-36 and 37/1 and 
41/j) are small, independent excavations 


into the bones surrounding the ethmoidal 
labyrinth They are similar to the rostral fron 
tal lacnmal and sphenoidal sinuses, excavat 
mg the surrounding bone and maintaining 
their continuity with the nasal cavity via the 
ethmoidal meatuses One of the more prom- 
inent cells progresses rostrally into the 
medial ventral wall of the orbit, and finally 
invades the bony septum of the maxillary 
sinus 

Occasionally cells were observed as extensions into the 
basal lamina of the ethmoid bone They were also observed 
ventral to the ethmoid meatuses extending Into the pala 
one bones In the region of the vomeroethmold and vomero- 
palatine sutures (Fig 37-41/j) Occasionally small, poorly 
developed excavations were found within the rostromedial 
wall of the orbit (Hillmann, J971) 


DORSAL CONCHAL SINUS 

The dorsal conchal sinus (Figs 37-40/F, 
41/k and 44 (white I) is an excavation within 
the nasal, ethmoid and, occasionally, the 
frontal bones It consists of a conchal portion 
and a nasal portion 

The conchal part, lying within the cavity of 
the first endoturbinate is large in the imma 
ture specimen It widens and extends ros- 
trally from the level of a transverse plane 
passing through the first and second molars 
to the level of a transverse plane passing be 
tween the third and fourth premolars In the 
mature specimen it is compressed laterally 
and shortened caudally, thus being reduced 
in size Its greatest part in the mature speci- 
men occurs at the level of a transverse plane 
passing between the second and third molar 
teeth 

The nasal part occupies the caudal part of 
the nasal bone and is continuous caudally 
with the conchal part In the mature speci 
men its size is reduced, and it does not extend 
rostrally beyond the level of a transverse 
plane passing through the first molar tooth 


B1BUOGRAPHY 

Earoti«R.l«« Compare* d*. JUminifere. DomMtJijue. 

Tom* Premm 0»<*o!ot> Lyon. UbanuAn tTAnaiomle Erd* 
Na jonale V eterina-re. 

*d VoL J Milano Caw Ed trtce Dortor Franc**.-*. VaX- 
an^the Other D*m«oc An.maK 2nd ed. Chlcafo Alexander 

H 01 th * "“I e»vjtw* and 
jraraitaui «irmre* of the dome* tic m rS«» «r rofa Joramitai 
. ZZ m’JTr library A me*. 

L«bre M F IS ,7 ComnUnion a I crude dr tnutcatim du iqoil 
dnmmmlnn domMOque* prtncpsjrment aua pom it 

f’.ii™ 1 " "• u 

Lo*«*r K. 1959 Zor Toposraphi* der *>aaenhohle vtA Act Na*eo- 

Preu»* F andK. D Budnre. J9€W Zor iiometo&t d*« Ifufihocken 
undandcrerKoochertpunMedca Uimbdni Bert Manch_Tl*r 
and. W rxbentch- 42 1 4 1 J « 



CHAPTER 


PORCINE 

SYNDESMOLOGY* 

by S. Sisson 


JOINTS AND LIGAMENTS 
OF THE VERTEBRAE 

The nuchal ligament is represented by a 
fibrous raphe and thin layers of elastic tissue 
which extend between the cervical spines 
The atlantooccipital and atlantoaxial joints 
resemble those of the dog 
The interspinous ligaments of the neck are 
elastic 


ARTICULATIONS OF THE THORAX 


The second to fifth or sixth costochondral 
joints aie synovial The intersternal articula- 
tion and sternal ligaments resemble those of 
the ox 


ARTICULATIONS OF THE 
THORACIC LIMB 


SHOULDER JOINT 

The joint capsule communicates so freely 
with the bicipitoradial bursa that the latter 
may well be regarded as a pouch of the cap- 
sule There is a rudimentary marginal 
cartilage around the nm of the glenoid 
cavity The cranial part of the capsule is 
reinforced by cruciate bands 


interosseous ligament as to prevent any 
appreciable moveftient between them 


CARPAL JOINTS 

These have the same general arrangement 
as in the horse Numerous minor differences 
exist but are excluded from this bnef account, 
which contains only important special 
features 

Two oblique, somewhat elastic bands 
cross dorsal to the radiocarpal and inter 
carpal joints The proximal one is attached 
to the distal end of the radius and passes 
distally and laterally to the ulnar carpal bone, 
the other one connects the radial and fourth 
carpal bones in a similar fashion 

The dorsal, palmar and interosseous carpal 
ligaments vary with the number of carpal 
bones present 


INTERMETACARPAL JOINTS 

The chief metacarpal bones of the pig 
articulate with each other at their proximal 
ends and are connected by interosseous 
ligaments which do not, however unite 
them closely, as m the horse 


METACARPOPHALANGEAL 

JOINTS 

There are foui metacarpophalangeal joints 
each of which has a capsule and collateia! 


ELBOW JOINT 

There are no important diflV rences The 
radius and ulna are so firmlv united bv the 


This chapter consists only of u hnef statement of the 
most important differences in the joints of the porcine 
In addition the nomenclaturt has m t been fully updated 
with tlut of the N \ \ H973) 


1251 



1254 


PORCINE 


intcrsesamoidean and phalangosesamoid 
ligaments Since distinct interosseous mus 
cles are present there are of course, no 
suspensory ligaments 


INTERPHALANGEAL JOINTS 

The interphalangeal joints of the chief 
digits resemble, in general those of the ox 
However, the distal mterdigital ligament 
resembles that of the sheep and is intimately 
adherent to the skin There is, besides a 
remarkable arrangement of ligaments which 
connect the small digits with one another and 
with the chief digits (Fig 38-1) 

This apparatus is somewhat complex, but 
its chief features are as follows A proximal 
interdigital ligament is attached on either side 
to the distal phalanges of the small digits 
while centrally it blends with the anular 
ligaments of the digital flexor tendons 
palmarly to the metacarpophalangeal joints 
of the chief digits Two bands (central 
longitudinal interdigital ligaments) anse on 
the bases of the small digits, cross the flexor 
tendons obliquely distally and centrally, pass 
through the proximal interdigital ligament 
and blend distally with the distal mterdigital 



I IGl'IlE 3S-1 I igament* and tendons of digits of 
pig, palmar %iew 

a. Superficial digital flexor tendon b. deep digital flexor 
tendon b , branches of b to accessory digits c c anular 
tig? d-d , ligg. of accessory digits e distal interdignal 
ligS , f f spiral band around flexor tendons of accessory 
digits g, abductor of accessory digit (From Ellenberger 
and Baum 1908 ) 


ligament Two collateral bands (collateral 
longitudinal mterdigital ligaments) are at- 
tached in common with the proximal mter- 
digital ligaments to the distal phalanges of 
the small digits and blend distally with the 
outer part of the distal mterdigital ligament 


ARTICULATIONS OF THE 
PELVIC LIMB 


SACROILIAC JOINT 

This joint and the pelvic ligaments present 
no striking differences 


HIP JOINT 

There are no important differences 


STIFLE JOINT 

Tile femoro patellar capsule is strongly 
reinforced on both sides by bands which 
blend with the collateral (femorotibial) liga- 
ments The cavity is continuous distally with 
that of the femorotibial joint A sagittal 
synovial fold (<*>rudimentum septi) extends 
up a short distance from the cranial cruciate 
ligament The suprapatellar pouch extends 
about 2 to 3 cm proximal to the trochlea, 
from this a pouch extends up beneath the 
quadriceps femons almost 2 5 cm and com 
municates through a large round opening 
with the joint cavity There is a strong patellar 
ligament which has a bursa under its distal 
part The tendon of the biceps femons takes 
the place of the lateral patellar ligament A 
small transverse ligament connects the 
cranial faces of the meniscL 

TIBIOFIBULAR JOINTS 

calsulJ’T’n "!? 1 JOmt ls Provided with a 
caudahv K '5 15 re , ,nforc «< cramally and 
caudal ly by fibrous tissue The interosseous 

bS aCl T L he s, ’ aft of lhe fibula "> 'he 

^ndude^,„ ,t,° f ' he V Wa - The J°"» 
included in the capsule of the hock joint and 

5 strengthened by dorsal and rianSir 
ligaments (41, g mailed, lateral /» dorsahs 
plamarls) ' which extend almost transversely 
from one bone to the other There is also an 
Interosseous ligament S0 an 


HOCK JOINT 


.ii . f L ^lhi " ' m £ ene ral, resemble- 
nr f,°^ he OX T i e m , edl2! ,1Bam ent consist: 
of a thin superficial part, which extendi 



38— PORCINE SYNDESMOLOGY 


1255 


almost vertically from malleolus to meta- 
tarsus, and a very strong deep part, which 
runs from the malleolus plantarlyand distally 
to the sustentaculum and talus. The lateral 
ligament also consists of two parts. The 
small superficial part extends from the 
malleolus distally to the lateral face of the 
body of the calcaneus. The stronger deep part 
arises from the dorsal part of the malleolus, 
passes chiefly plantarly, widens, and ends on 
a ndge on the lateral surface of the calcaneus. 
A strong band extends from the lateral face 
of the medial malleolus to a depression on the 
medial surface of the proximal part of the 
talus. An oblique dorsal band connects the 
central and fourth tarsal bones. 

The remaining joints resemble those of the 
thoracic limb. 


ARTICULATIONS OF THE SKULL 


TEMPOROMANDIBULAR 

ARTICULATION 

The considerable longitudinal diameter of 
the temporal articular surfaces and the very 


small size of the retroarticular process allow 
great freedom of protraction and retraction 
of the lower jaw. Transverse movement is 
limited. The caudal ligament is absent. 

The other articulations of the skull are 
sufficiently described in the Osteology 
chapter. 


BIBLIOGRAPHY 


Barone R 1968 AnatomleCotnparccdes Mimnilftrcs Domestiques 
Tome II Arthrologlr ct Myologi? Lyon, Laboratolre d Anatomic 
Ecole National? Vcterinalre 

Ellenberger, \\ . and II Baum 190S llandbuch dcr VerRlelchcnden 
Anainmle dcr llausticrc Berlin ton August Iiirschwald. 

Kostyra J I9G1 Limb Joints of the put I Tore limb- Ann Unit M 
Curie-Sklodowska. Sect DD J4 123-265 

Kostyra J 1962 Limb joints of the pie- II Hind limb Ann Unh M 
Curie-Sklodow ska. Sect DD 15 137-190 

Lange, X 1960 Die Eniwirklune der Itippenknorpclaclcnke bclm 
Schwein. Anal. Anz 108 172-201 

Wlssdorf II 1965 Das Knicgelcnk dcs School lies AnatomisChc 
Crundlagen und InJcktlonsmoiJichkHt Deutsche tlerirztl 
Wschr 72 289-294 

Wiisdorf II 1965 Das EllboKengelcnk- Artlculatio cubill-dts 
Schweines Cnindhgen fiir die Gelenkfnjektion Deutsche 
tlerirztl. Wschr 72 5G9-570 

Wlsdorf. II I960. Das Tarsalgelenk dcs Schtvefnes Zbl Vet Med 
A 13 309-383 

\\ issdorf II I960 Das Karpalgelenk des Schueincs-Crundlagen 
fflr die Gelcnklnjektlon Deutsche tiemntl Wschr 73 396-401 



CHAPTER 39 


PORCINE 

MYOLOGY 

by S Sisson 

(with Ear Muscles by S S Gandhi) 


FACE 

The cutaneus faciei is pale thin and dif 
ficuU tD separate from the skin 

The orbicularis oris is little developed. 

The le» ator nasolabialis is thin and pale and 
undivided 

The levator labn maxillaris may well be 
termed the levator rostn It has a large 
pcnnate belly which arises in the canine 
(preorbital) fossa. The tendon ends on the 


rostral part of the os rostn A muscular slip 
connects it with the incisive bone 
The zygomaticus anses on the fascia over 
the masseter and ends at the angle of the 
mouth 

The depressor labn mandibularis separates 
from the buccinator only near the angle of the 
mouth it ends by a number of tendinous 
branches in the lower Up 
The caninus (former dilatator nans lateralis) 
is well developed It anses under the levator 



FIGURE 39-! Superficial muscles of pie after removal of cutaneus m. 

a Levator nasolabulis b levator labii maxillaris b fleshy slip of b which comes from incisive bone c caninus (dilata 
tor naris lateralis) d depressor labn maxillaris (depressor rostn) e orbicularis ons f depressor labii mandibularis g, 
zygoma ticus h. masseter i, i i brachiocephalicus (cleidooccipitalis cleidomastoideus clavicular part or deitoidei) k, 
stemocephahcus 1 sternohyoid eus m omotransversarius n. n trapezius o subclavius p latissimus dorst q thoraco- 
lumbar fascia t obhquus extemus abdominis r aponeurosis of r s serrat us donates t terra tus ten trails thoracis u 
pectorahs ascendent \ supraspinatus vv w deltoideus *, long head of tnceps brae hn y lateral head of tnceps brachii 
z tensor fasciae amebrachn 1 brachiahs 2 extensor carpi radiahs 3 extensor digit! IV 4 extensor digit! V 5 extensor 
carpi ulnaos 6 ulnar head of flexor d gitorum profundus 7 gluteus medius 8 tensor fasciae latae 9 JO 10 biceps 
femom II semitendmosus J2 semimembranosus |3 sacrocaudales 14 panruculus adiposut in section. (From Ellen 
berger li tOS ) 

1256 



39 -PORCINE MYOLOGY 


labii maxiUaris and ends by a tendinous 
network around the nostril. 

The dilatator naris apicalis (former trans- 
versus nasi) is represented by only a few 
fibers which cross over the os rostri. 

The depressor labii maxillaris (depressor 
rostri) arises on the facial crest. It has a 
long, strong tendon which passes ventral 
to the nostril and turns dorsomedially to 
meet the tendon of the opposite side and end 
in the skin of the snout. It depresses the 
snout and contracts the nostril. 

The malaris is absent, and the other palpe- 
bral muscles present no special features. 

Mandibular Muscles 

The masseter is thick. 

The pterygoideus medialis is wide at its 
insertion. 

The pterygoideus lateralis is large and 
distinct. 

The occipitomandibular part of the digas- 
tricus arises on the jugular process of the 
occipital bone and ends on the medial and 
ventral surface of the mandible rostral to the 
groove for the facial vessels. 

Hyoid Muscles 

The mylohyoideus consists of two more or 
less distinct layers, the superficial one being 
the d>transversus mandibulae. 


1257 

The occipitohyoideus and ceratohyoideus 
are small. 

The byoideus transversus is absent. 

The omohyoidcus and stcrnohyoideus are 
referred to in connection with the muscles 
of the neck. 

EAR 

by S. S. Gandhi 

AURICULARES ROSTRALES 

(Figs. 39-2 and 3) 

The zygomaticoauricularis is a small strip 
of muscle as compared to that pf the small 
ruminants and is of uniform size. 

Origin: From the zygomatic arch and then 
curves cau dally along the caudal border of 
the auricular cartilage. 

Insertion: To the distal third of the base of 
the caudal border of the auricular cartilage, 
lying rostral to the insertion of the parotido- 
auricularis. Its insertion is not in common 
with the parotidoauricularis. 

Structure. At its origin the muscle fibers 
overlap with those of the scutuloauriculares 
superficiales. It is narrower at its insertion 
than at its ongin. 

The scutuloauriculares superficiales are 
well developed. 



FIGURE 39-2. Muscles of ear of pic, lateral superficial >iew. 

,. i ^\ Le I tUQraT1 ? uli ocul1 mcdu!,s - orbicularis ocull. c. Jmerscutularis. d, frontoscutularis. e.cervicoauriculam suDcrf. 

superficiales. i. * iwrIcus (Nikolai. 1954). k. * hellc.s (outer poofon) m TwohSt* 
SmistrilEy "^«^' icoaurtcul " 1 ‘- 0 * auricwlarc3 «‘ la ^. p, parotidoauricularis, q. parotid s . Uutuhrcartll a R e 



1258 


PORCINE 


e 



a, Uvawr aneuli ocuU medial... b. orblcuUri. oculi. c. Intmctitulail* d. frontMcutulari* and d . Iti itfl »««». * 
vlcoauriculari* .uperficiallt, h, .cutuloauriculare. .uperficiales and h , ihelr In.tiUon, 1, 4 tragi cus (Nikolai. 1954,1, k. 
4 htttriv (outer ponlon\ rn. 6 tragohelicW. (Nikolai. 195d>. n. tygomatlcoauricularl*. o, auricular cartilage, p. pan> 
tidoauricularli, q parotid gland, r, .cutuloauriculare* profundi. •, acutular cartilage (Illustration by Godlnho ) 


Origin: Mainly from the dorsal surface of 
the scutifoTm cartilage, although some fibers 
originate from the zygomatic arch in common 
with the zygomaticoauricularis. These fibers 
ascend dorsally along the rostral border of the 
auricular cartilage. 

Insertion; To the distal third of the rostral 
border of the auricular cartilage at its medial 
aspect. 

The scutuloaurieutares profundi lie on the 
deep surface of the scutiform cartilage and 
are covered by It at Its point of origin Then 
its fibers stretch toward the caudomediai 
face of the auricular cartilage and are inserted 
to the caudomediai face of the prominence at 
the base of the auricular cartilage. 

The fronloscutularis is a well-developed 
muscle 

Origin: From the frontal crest. 

Insertion: To the rostromedial part of the 
dorsal surface of the scutiform cartilage 


AURICUIARES OORSAIES 

(Fig 39-4) 

The interscutularis, inan aged pig, was seen 
to be a thick, well-developed muscle with its 
fibers directed irregularly ventrally and 
cau dally. 

Origin* From the frontal part of the tem- 
poral hne and then crosses to the medial 


aspect of the opposite side lying partly over 
the ceivicoauncularis superficialis 

Insertion • To the rostromedial aspect of the 
dorsal surface of the scutiform cartilage. 

The parietoauricularis Is a deeper muscle 
lying under the cervicoauricularis and 
scutulans superficialis. 

Origin. From the parietal part of the tem- 
poral line. 

Insertion To the dorsal convex surface of 
the auricular cartilage at its base. 


AURICUIARES CAUDAiES 

The cervicoscutularis is a thin muscular 
sheet. 

Origin • From the fascia of the atlantoaxial 
region and extends rostrad, lying over the 
cervicoaunculans superficialis. 

Insertion To the caudomediai aspect of 
the dorsal surface of the scutiform cartilage 
and covered by the interscutularis 

The cervicoauricularis superficialis is very 
well-developed in the pig. 

Origin • From the nuchal crest and the 
fascia of the nuchal region and then extends 
caudomedially and is covered by the inter- 
scutulans and cervicoscutularis super- 
ficiahs 

Insertion • To the caudomediai part of the 
distal third of the dorsal surface of the 



39 -PORCINE MYOLOGY 


1259 


auricular cartilage, while its second part is 
inserted to the caudolateral aspect of the 
auricular cartilage near its base. 

N erve Supply: Caudal auricular n. 

The cervicoauricularis medius is a well- 
developed muscle lying caudal to the cervico- 
auricularis superficialis. 

Origin; In common with the cervicoauricu- 
laris superficialis, arising from the deeper 
aspect of the nuchal fascia and the nuchal 
crest. It curves toward the caudolateral aspect 
of the auricular cartilage. 

Insertion: To the caudolateral aspect of the 
dorsal surface of the auricular cartilage just 
dorsal to the caudal eminence at the base of 
the ear. 

Nerve Supply Caudal auricular n. 

The cervicoauricularis profundus is a well- 
developed muscle lying under the cervico- 
auricularis superficialis and medius. 

Origin: From the deep face of the parietal 
portion of the temporal line and the occipital 
bone. 

Insertion: The major portion to the caudo- 
medial aspect of the caudomedial eminence 
at the base of the ear; some fibers to the 
caudolateral aspect of the eminence. 



p 


FIGURE 39-5. Muscles of ear of pig, dorsal deep 
view. 



FIGURE 39—1. Muscles of ear of pig, dorsal super- 
ficial riew. 


c, InicrscutuUrls; c. cer\ icoauriculam superficialis, ! 
erncoauricularl* medius; g. ten Icoauricularis pn 
P. auricular cartilage: p, parmidoauricutaris; < 
paroud gland, *. scutular cartilage, i, trapezius; u. cc: 
vicoscutuUri* (Illustration by Codlnho ) 


e, Cervicoauricularis superficialis; f, cervicoauricularis 
medius; g. cervicoauricularis profundus; j, $ antitraglcus 
(Nikolai, 1954), n, zygomaticoauricularis . o, auricular car- 
tilage, p. parotidoauncularis, q, parotid gland; r, scutu- 
Joaunculares profundJ; s, scutular cartilage; t, trapezius; 
v, <t> traits versl et obllqui auriculares (Nikolai, 1954), tv, 
auricular adipose body. (Illustration by Godinho ) 


Structure: Its fibers extend ventrad. 
Nerve Supply: Caudal auricular n. 


AURICULARES VENTRAIES 

The styloauricularis is a thin sheet of 
muscle lying along the rostral part of the 
parotid gland. 

Origin: From the fascia covering the rostral 
part of the parotid gland and the angle of the 
mandible. 

Insertion: In common with the parotido- 
auricularis to the middle of the caudolateral 
eminence of the auricular cartilage at its base. 

Structure: It ascends dorsally, and just 
ventral to the base of the ear its muscle fibers 
unite with the parotidoauncularis. 

Nerve Supply: Caudal auricular n. 

The parotidoauncularis is a small, thread- 
like, long, muscular sheet which is embedded 
In the parotid gland. 

Origin: From the fascia of the ventral part 
of the parotid gland and extends dorsally. 

Insertion; In common with the stylo- 
aurlculans. 

Structure: It is longer than the stylo- 



PORCINE 


1260 

aunculans with which U unites about 5 cm 
\ entral to the base of the ear 

by S Sisson 

NECK 

(Figs 46-16 and 19) 

The cutaneus colli consists of two layers 
which cross each other obliquely The fibers 
of the superficial layer are directed nearly 
vertically those of the deep layer toward 
the face on which they are continued to form 
the facial portion 

The brachiocephalicus is described with the 
muscles of the shoulder girdle 
The sternocephalicus arises on the sternum 
and is inserted by a long round tendon on the 
mastoid process 

The thyroid part of the sternothjrohjoideus 
has a peculiar arrangement It arises (sep- 
arately from the opposite muscle) on the 
manubnum of the sternum About the middle 
of the neck it has an oblique tendinous 
intersection beyond which it divides into two 
branches one of these is inserted in the 
usual fashion the other ends on the laryngeal 
prominence The hyoid part is well developed 
The omoh> oideus is thin It arises as in the 
horse but has no connection with the brachio- 
cephalicus or with the opposite muscle 
The omotransversarms arises on the first 
or second cervical vertebra (under cover of 
the brachiocephalicus) and is inserted into 
the ventral part of the scapular spine 

There are twosealeni The scalenus ventrahs 
resembles that of the ox, is attached to the 
last four cervical vertebrae and is perforated 
by the nerves of the brachial plexus The 
scalenus dorsalis arises on the transverse 
processes of the third to sixth cervical verte 
brae and ends on the third nb 

The ventral muscles of the head present no 
special features 

The longua colli is separated from the op- 
posite muscle, so that parts of the bodies of 
the cervical vertebrae are exposed as in man 

The intertransversani resemble those of 
the ox. 

The aplemus cervicis is thick and extensive 
It ends in three parts on the occipital and 
temporal bones and on the wing of the atlas 
(inconstant) 

The longissimus capitis et allantts is small, 
its atlantal part is blended with the longis 
simus cervicis 

The semispinalis capitis is large and is 
clearly divided into two parts the dorsal 
part (biventer cervicis) is marked by several 
tendinous intersections, the ventral part is 
the complextis 

The obltqaus capitas caudalis is relatively 
thin 

The recti capitis dors ales are thick and more 
or less fused 


The Ievatores costarum and rectus thoracis 
present no special features 
The intercostales extemi are absent under 
the serratus dorsalis and the digitations of the 
obliquus extemus abdominis 
The intercostales interni are thick between 
the cartilages of the sternal ribs 
The retractor costae and the transversus 
thoracis resemble those of the horse, the 
latter extends caudad to the eighth cartilage 
and fuses with the transversus abdormms 
The diaphragm has seven costal digita 
tions on each side, the caudal ones being 
attached to the nbs at some distance (about 
one third to one fourth of nb length) from the 
costochondral articulation * The line of 
attachment reaches the latter at the tenth nb 
and passes along the eighth cartilage to the 
xiphoid process The tendinous center is 
more rounded than in the horse The crura 
are well developed The nght crus is very 
large and is perforated by the extensive 
slit Uke esophageal hiatus, which is median 
in position and lies about 6 to 8 cm ventral 
to the twelfth thoracic vertebra. A serous sac 
is found in the esophageal hiatus, usually to 
the nght and ventral to the esophagus, ex 
tending from the stomach craniad between 
the pleurae a distance of 7 5 to 10 cm, this sac 
may be in the form of a synovial sheath in 
older subjects and be of greater extent both 
cramaliy and caudally The aortic hiatus is 
between the crura. 


ABOOMEN 

(Fig. 46-19) 


The abdominal tunic is little developed 
The obliquus extemus abdominis has an 
extensive fleshy portion and acorrespondingly 
narrow aponeurosis, the latter does not 
detach a femoral lamina, but is reflected in 
toto to form the inguinal ligament 
The obliquus intemus abdominis (Fig 46- 
18) resembles that of the ox. A small fusiform 
muscle, which crosses the inguinal canal 
obliquely and is attached on the abdominal 
surface of the inguinal ligament, is apparently 
a detached slip of the obliquus Internus 
abdominis 

The rectus abdominis is extensive and thick. 
It has seven to ten inscriptions Its tendon of 
insertion fuses largely with the common 
tendon of the gracfles and does not give off 
an accessory band to the head of the femur 


•It is Interesting to note that the diaphragm ha* n o 
attachment to the fifteenth rib which is often present 
and well developed. 



39— PORCINE MYOLOGY 


1261 



sixth caudal vertebrae of pig. 

A, Cutaneous v., B, dorsolateral caudal a , C, ventrola- 
teral caudal a ; D, middle caudal a and v ; 1, sacrocaudalis 
dorsalis medialis; 2, sacrocaudalis dorsalis lateralis, 3’, in- 
tertransversani ventrales caudae; 3', intertransversarii 
dorsales caudae, 4, sacrocaudalis ventralis lateralis, 5, 
sacrocaudalis ventralis medialis (From Getty, 1964 ) 


The fleshy part of the transversus abdominis 
is well developed. It blends cramally with the 
transversus thoracis. 

The cremaster (extemus) is present in the 
female as well as in the male. 

DORSUM AND IOINS 

(Figs. 46-19 and 24) 

v The serratus dorsalis cranialis is inserted 
into the fifth to eighth nbs inclusive, the 
serratus dorsalis caudalis into the last four or 
five ribs. There are usually no digitations 
attached to the ninth and tenth nbs. 

The iliocostalis thoracis and lumborun^ 
(longissimus costarum) extends to the wing 
of the atlas (Fig. 46-18). 

The spinalis et semispinalis can be sep- 
arated without much difficulty from the 
longissimus (dorsi), the division from the 
common mass of the loins beginning about 
the first lumbar vertebra. 

The multiiidus resembles that of the horse. 

Interspinates are present, as well as distinct 
intertransversarii of the dorsum and loins. 


TAIL 

(Figs. 39-6, 7, and 8) 

There are essentially two main groups of 
muscles of the tail— caudal (coccygeal) 
muscles of the vertebral column and coccy- 
geal muscles of the pelvis (Getty and Ghoshal, 
1967).* 

The muscles of the caudal vertebral column, 
composed of elevators, depressors and lateral 
muscles of the tail, extend dorsally, laterally 
and ventrally along the caudal vertebral 
column in a segmental arrangement between 
individual vertebrae. These muscles are: 

The sacrocaudalis (sacrococcygeus) dor- 
salis medialis, considered to be the caudal 
continuation of the multifidus, is initially 
difficult to distinguish or separate from the 
caudal continuation of the multifidus seg- 
ments. 

The sacrocaudalis dorsalis lateralis repre- 
sents the longissimus in the caudal region. 
This muscle, lying lateral to the sacrocaudalis 
dorsalis medialis, arises from the last sacral 
vertebra and continues in the tail area by a 
senes of individual tendons. 

The intertransversarii dorsales et ventrales 
caudae are located between the transverse 
processes of the caudal vertebrae. 

The sacrocaudalis ventralis lateralis is 
better developed than the sacrocaudalis 
ventralis medialis. It anses as a strong, 
bilaterally compressed muscle from the 
second to third (often from the first to fourth) 
sacral vertebrae along the ventral surface 
of the sacrum and extends to the transverse 
processes of the first to eleventh caudal 
vertebrae. 

The sacrocaudalis ventralis medialis is 
poorly developed as compared to the sacro- 
caudalis ventralis lateralis. Lying medial to 
the sacrocaudalis ventralis lateralis, it is 
located on the ventral surface of the tail, 
where it forms a groove with its fellow of the 
opposite side. This same groove also contains 


•Gurlt (Sisson, 1910) explains the twist of the tail as 
being due to the spiral arrangement of the insertions of 
the tendons 




1262 


PORCINE 



FIGURE 39-8 Coccjgeal muscles of pig 

B «crum C fim caudal vertebra D fifth caudal vertebra Z os coxae F iwlnatoc tuber a cocc^scus a levatotanl 
b sphbwter anl extemus c rectum 1 middle caudal a 2 middle caudal v (From Getty and Cfcoshal, 1B67 ) 


the caudal vessels (unpaired middle caudal 
artery and paired \ em) 

The coccygeal muscles of the pelvis are 
made up of the coccygeal muscles of the tail, 
which consist of the coccygeus and levator 
ani muscles 

The coccjgeus (coccygeus lateralis, ischio- 
coccygeus) arises from the medial surface of 
the Ischlatic spine and the broad sacrotuberal 
ligament close to the ischlatic spine It fans 
out dorsally, to be inserted on the transverse 
processes of the first to fourth caudal \erte 
brae and on the caudal Fascia after passing 
between the intertransversani ventrales 
caudae and sacrocaudalis v entrails lateralis 

The levator am (coccjgeus medialis 
Tetractor anl) is thicker than the coccjgeus, 
lies medial to it, and is separated from it by 
an aponeurotic sheet It is a flat muscle lying 
on the medial side of the ischlatic spine, with 
fibers extending to the obturator foramen It 
inserts on the fourth and fifth caudal 
vertebrae and, by means of the caudal fascia 
to the anus 


THORACIC APPENDAGE 

Shoulder Girdle 
(Fig 46-16) 

The trapezius is v ery wide, its line of origin 
extending from the occipital bone *o the tenth 
thoracic vertebra. There is no clear division 


between its two parts, which are both inserted 
into the scapular spine 
The omotransversarius resembles that of 
the ox 

The rhomboideus consists of three parts 
The cervical part (rhomboideus cervicia) is 
greatlj developed Its origin extending from 
the second cervical to the sixth thoracic 
vertebrae The cephalic part (rhomboideus 
capitis) arises with the splemus on the 
occipital bone and is inserted with the cervi 
cal part The thoracic part (rhomboideus 
thoracis) extends as far caudad as the ninth 
or tenth thoracic vertebra. 

The latissimus dorsi is attached to the four 
ribs preceding the last It is inserted into the 
lesser tubercle of the humerus 
The brachiocephahcus divides into two 
parts, the ctevdomastoideus and cleido- 
oeeipit&lis, which arise on the mastoid process 
and nuchal crest respectively, and unite at 
the fibrous vestige of the clavicle 
The pectoraiis descendens is thin The 
pectoralis transversus is divided into two 
parts, one of which ends on the humerus, 
the other on the fascia of the forearm The 
subclarius resembles that of the horse, but 
its ongin does not extend caudal to the first 
two sternocostal articulations The peclo- 
ralis ascenders is very long 
The cervical part of the serratus ventralis 
is greatly dev eloped, its ongin extending from 
the wing of the atlas to the dorsal part of the 
fifth nb. and passing under the thoracic part, 
the latter resembles that of the ox 



39 -PORCINE MYOLOGY 


1263 


Shoulder 

The deltoideus is undivided, it arises from 
the aponeurosis covering the infraspinatus, 
and it ends largely on the deltoid ndge, but 
partly on the fascia of the arm 
The supraspmatus is large, it has a small 
attachment to the lesser tubercle and ends 
chiefly on the greater tubercle of the humerus 
There is a bursa between the tendon and the 
cranial part of the greater tubercle 
The infraspinatus is wide, it is inserted into 
a depression \entral to the caudal division 
of the greater tubercle There is a bursa 
between the tendon and the tubercle 
The teres minor is large and rounded, it 
ends on a tubercle between the greater 
tubercle and deltoid tuberosity of the 
humerus 

The subscapularis is very broad at its dorsal 
part It extends caudally to the caudal angle 
of the scapula, but cranially only about two- 
thirds of the way to the vertebral border 
The teres major presents nothing remark 
able 

The coracobrachiahs is short wide and 
undivided There is a bursa between its 
broad tendon of ongin and the tendon of 
insertion of the subscapulans 
The articularis humeri (capsulans) is 
variable, it may be about 1 5 cm wide or very 
small and is frequently absent 


Arm 

The biceps brachn is fusiform and not 
greatly developed Its tendon of ongin is 
rounded and the underlying bursa com 
murucates so freely with the shoulder joint 
as to be regarded as an evagination of the 
synovial membrane of the latter A small 
band binds down the tendon in the bicipital 
groove The tendon of insertion di\ ides into 
two branches One branch passes caudad 
across the medial surface of the neck of the 
radius to end on the proximal extremity of 
the ulna The other is attached to the radius 
under cover of the brachialis tendon 

The brachialis is large Its tendon of in 
scrtion divides The small branch is inserted 
into the medial border of the radius distal 
to the biceps tendon The large branch crosses 
the medial border of the radius and ends on 
the medial surface of the ulna distal to the 
biceps tendon, there is a bursa under this 
tendon 

The tensor fasciae antebrachu resembles 
that of tiie horse but is very wide and bends 
around the caudal border or the triceps 
brachii 

The long head of the triceps bracho is 
inserted into the summit of the olecranon b> 
t"o tendons, between which there is a 
synovial bursa The lateral head is inserted 


into a crest on the lateral surface of the 
olecranon by a thin tendon, under which there 
is a bursa The medial head arises from the 
proximal third of the medial surface of the 
humerus, it is inserted into the medial 
surface of the olecranon by a short tendon, 
under which there is a small bursa 
There are two anconei 


Antebrachium and Manus 

The extensor carpi radiahs is a strong 
fleshy muscle the tendon of which is m 
serted into the proximal end of the third meta 
carpal bone It may be divided into two parts 
-(extensor carpi radiahs longus, brevis) 

The abductor digiti I longus (extensor carpi 
obhquus) is well developed, itanses from the 
distal two thirds of the lateral surface of the 
radius and ulna and ends on the second meta 
carpal bone 

The extensor digitorum communis arises 
on the lateral epicondyle of the humerus and 
the lateral collateral ligament of the elbow 
and divides into three parts The tendon of 



FIGURE 39 ~ 9 Musdes of antebrachium and 
manusofpifj dorsolateral % lew 


« - jhomjj* o aixiuctor dfgfti I Jongus 

C d e exten sor digitorum com 
munis c c tendons of Insertion of c d d tendons of d 
Lr e rfi!S M £ fe f tcnd ° nof extensor digitill g exten 

!>. 1 c ?tensor digiti V h tendon of h I ten 
dinous and k flesh} part of ulnaris lateralis k tendon of 
hea lr°^ < 1 CXOr Riorum profundus m flexor 
1908) SUperf,cia,1$ n brachlal1 * (From EUenberger 



PORCINE 


1264 

the medial head ends chiefly on the third 
digit but commonly sends a small branch to 
the second. The tendon of the middle head 
divides more dtstally into two branches for 
the third and fourth (chief) digits proximal 
to this bifurcation it detaches a small branch 
to the second digit, which usually unites with 
the tendon of the extensor digiti II The ten 
don of the deep head divides into two 
branches the medial one joining the tendon 
of the middle head while the lateral one ends 
on the fifth digit 

The extensor digiti II is covered by the pre 
ceding muscle, with which it is partially 
fused It arises on the ulna. Its delicate ten 
don usually unites with the tendon of the 
middle head of the extensor digitorum com 
mums which goes to the second digit 
The extensor digitorum lateralis consists 
of two distinct parts (1) The large super 
ficial part has a long tendon which ends on 
the fourth digit and often sends a slip to the 
fifth digit (2) The small deep part ends by a 
long tendon on the lateral aspect of the fifth 

digit 

The supinator, when present is a pale 
thin muscular slip which arises on the lateral 
border of the radius just proximal to the inter 
osseous space and extends medially and ven 
traUy across the dorsal surface of the bone to 
its medial border where it blends with the 
radial head of the flexor digitorum profundus 
The pronator teres is a delicate, fusiform 
muscle which lies along the medial surface 
of the elbow and proximal part of the forearm. 

It arises from the medial epicondyle and me 
dial collateral ligament of the elbow and is 
inserted by a thin tendon to the medial border 
of the radius about its middle 
The flexor carpi radialis is well developed It 
arises on the medial epicondyle of the 
humerus and is inserted into the third meta 
carpal bone 

The flexor carpi ulnans Is narrow and usu 
ally has no ulnar head It runs obliquely dis 
tally on the caudal side of the forearm in the 
furrow between the flexor digitorum super 
iicialis and profundus It arises from the 
medial epicondyle of the humerus and ends 
on the accessory carpal bone 
The ulnaris lateralis (extensor carpi ul 
naris) is covered by a tendinous band, which 
is a thickened part of the fascia of the forearm 
and extends from the lateral epicondyle to 
the accessory carpal bone and lateral aspect 
of the carpus The belly of the muscle is 
round, its tendon of insertion perforates this 
band in the distal part of the forearm and 
ends on the proximal end of the fifth meta 
carpal bone 

The flexor digitorum superficialis arises 
from the medial epicondyle of the humerus 
and consists of two parts The tendon of the 
superficial head passes distally bound down 
by a fascial thickening the flexor retinaculum. 


It forms a ring at the fetlock for a tendon of 
the flexor digitorum profundus and ends 
by two branches on the middle phalanx of the 
fourth digit It receiv es a small band from the 
accessory carpal bone The tendon of the 
deep head after detaching a strong branch to 
the tendon of the flexor digitorum profundus, 
passes distally with the latter (for which it 
forms a nng) and ends on the third digit 
The flexor digitorum profundus has three 
heads-humeral ulnar and radial The hu- 
meral head is very large and forms the greater 
part of the contour of the caudal face of the 
forearm It consists of two parts — a large 
superficial part and a much smaller deep 
part which anses with the flexor digitorum 
superficialis Each ends at the distal part of 
the forearm on a short tendon These unite 
and receive the tendons of the radial and 
ulnar heads and a branch from the superfi 
cial digital flexor tendon The ulnar head has 
a short, thick prismatic belly which arises 
from the medial surface of the proximal 
part of the ulna. Its long thin tendon passes 
distally on the humeral head and joins the 
tendon of the latter at the level of the acces 
sory carpal bone The radial head is small 
It anses from the proximal part of the medial 
border of the radius and from the deep fascia, 
and its tendon joins that of the humeral head 
at the distal end of the forearm The common 
tendon divides into four branches the larger 
central pair ending on the distal phalanges of 
the principal digits the smaller abaxial pair 
on the accessory 7 digits The latter are bound 
down by a peculiar spiral band The carpal 
sheath envelops the tendon of the flexor 
digitorum profundus and that of the deep part 
of the flexor digitorum superficialis It ex 
tends from the distal third of the forearm to 
the distal third of the metacarpus At the prox 
imal part of the metacarpus a small mus 
cular band extends from the deep digital 
flexor tendon to the tendon of the deep part 
of the flexor digitorum superficial^ Another 
muscular bundle passes from the deep digi 
tal flexor tendon to the second digit 
The lumbncales are represented by bundles 
which extend from the deep digital flexor 
tendon to the tendon of the deep head of the 
flexor digitorum superficialis 
The third and fourth interossei are present. 
Each sends two slips to the corresponding 
sesamoid bones and extensor tendon 
There are flexors, adductors and abductors 
of the second and fifth digits 


PELVIC APPENDAGE 


Sublumbar Muscles 

The pupas minor is intimately united with 
the psoas fqajor cranially and has a long small 



39 -PORCINE MYOLOGY 


1265 


tendon which ends on the psoas tubercle. It 
has no thoracic part. 

The psoas major is large and rounded. It 
begins at the last rib. 

The quadratus lumborum is well developed 
and extends to the last three or four thoracic 
vertebrae. 

Hip and Thigh 

(Fig. 46-16) 

The tensor fasciae latae is broad, and its 
fleshy part reaches almost to the patella. 

The gluteus superficialis has a sacral head 
only; it blends with the biceps femoris. 

The gluteus medius has a small lumbar 
part which does not extend so far craniad as 
in the horse. The deep part (gluteus acces- 
sorius) is clearly marked. 

The gluteus profundus is extensive, reach- 
ing nearly to the coxal tuber. 

The biceps femoris has a narrow origin 
from the broad sacrotuberal ligament and 
ischiatic tuber. It ends ventrally like that of 
the ox. 

The semitendinosus has two heads like that 
of the horse. 

The semimembranosus arises from the is- 
chiatic tuber and has two insertions, as in the 
ox. . . , 

The sartorius has two heads of origin, be- 
tween which the external iliac vessels are 
situated. The medial one arises from the ten- 
don of the psoas minor, the lateral one from 
the iliac fascia. 

The graciles are united at their origin even 
more than in the ox. 

The pectineus is well developed and is flat- 
tened from craniad to caudad. 

The adductor shows no division and is 
partially fused with the gracilis. It ends on 
the femur just dorsal to the origin of the 
gastrocnemius. 

The quadratus femoris is large. 

The obturatorius externus resembles that 
of the horse. 

The obturatorius internus is extensive and 
strong; its tendon emerges through the ob- 
turator foramen. 

The gemellus is fused in part with the ob- 
turatorius internus. 

Tile quadriceps femoris is more clearly 
divided than in the horse, and its action is 
transmitted by a single patellar ligament. 
The articulnris coxae (capsularis) Is absent. 


leg and Foot 

Tin* fibulari** (peronetiO terflus is a well* 
developed muscle which Is. in great part, 
superficially situated on the cranial aspect 
of the leg. It covers the extensor digltorum 



FIGURE 39-10. Muscles of leg and foot of pig; 
dorsolateral view. 

a, Tibialis cranialis; a', tendon of preceding; b, fibularis 
tertius; b'. tendon of b; c, extensor digltorum longus; d, e, 
f. r, r, tendons of c; g, fibularis longus; g\ tendon of g; h. 
extensor digiU IV; h', tendon of h, which receives h* from 
the interosseus medius; i, extensor digit! V; k, flexor digi- 
torum profundus; 1, soleus; m. gastrocnemius; n, exten- 
sor digltorum brevis. (From Ellenberger, 1908.) 


longus, with which it is united except in the 
distal third of the leg. It arises from the ex- 
tensor fossa of the femur by a common ten- 
don with that muscle, a synovial pouch from 
the femorotibial joint extending under the 
origin. 

This sac is about 3 to 4 cm in length In large subjects and 
extends around the lateral edge of the tendon to its super- 
ficial face, so as to make a partial sheath and underlie the 
origin of the fibularis longus also. 

The muscle is continued at the distal end 
of the leg by a strong tendon which passes 
over the flexion surface of the hock, between 
the tendon of the extensor digitorum longus 
(lateral) and that of the tibialis cranialis 
(medial), all three being bound down by a 
strong anular ligament which extends across 
from one malleolus to the other. It ends by 
two or more branches on the first and second 
tarsal and third metatarsal bones. Not rarely 
there is a thin tendon inserted into the fourth 
metatarsal bone. The tendon usually receives 
a small branch from that or the tibialis crani- 
alis at the anular ligament. 



The tibialis cramahs is smaller than the 
preceding It arises from the lateral surface 
of the tuberosity and lateral condyle of the 
tibia. At the distal end of the leg the tendon 
passes under the anular ligament mentioned 
above (where it detaches a small branch to 
the fibulans tertius) and ends on the second 
tarsal and the proximal end of the second 
metatarsal bone The terminal part passes 
under a superficial layer of the medial co! 
lateral ligament of the hock and is provided 
with a bursa 

The fibulans (peroneus) longus descends 
cranial to the fibula and the extensor digi 
torum lateralis It arises chiefly from the lat 
eral condyle of the tibia. The tendon of in 


the fibula the lateral collateral femorotibial 
ligament and the intermuscular septum be- 
tween this muscle and the flexor digitorum 
profundus It consists of two parts The super, 
ficial larger part has a tendon which appeals 
a little distal to the middle of the leg, descends 
on the grooved lateral surface of the fibula, 
inclines cranially, crossing under the tendon 
of the fibulans longus, and ends on the ex- 
tensor process of the distal phalanx of the 
lateral chief (fourth) digit It receives an 
interosseous tendon (extensor slip) at the 
proximal phalanx The tendon of the deep 
part accompanies that of the superficial one 
to the tarsus and descends to the lateral ac- 
cessory (fifth) digit 


sertion descends through a groove on the 
lateral malleolus crosses over the tendons 
of the extensor digitorum lateralis, then under 
the lateral collateral ligament to the plantar 
surface of the hock to end on the first tarsal 
bone There is a bursa under the tendon 
where it lies in the groove on the fourth tarsal 
The muscle is a flexor of the hock. 


Hie two tendons are bound down at the lateral malleoli* s 
by an anular ligament The superficial tendon may receive 
a branch of the long digital extensor tendon and send a 
tendon to the fifth dlglL The caudal tendon may send „ 
reinforcing branch to the long digital extensor tendon for 
the fifth digit There may be a third small head which arise* 
from the middle of the fibula and sends a delicate tendt> n 
to Join that of the deep head. 


The extensor digitorum longus arises in 
~ common with the fibulans tertius, by which 
it is largely covered and with which it is 
united to the distal third of the leg Three 
tendons appear at the proximal extensor 
retinaculum and extend distally and a little 
medially over the flexion surface of the hock. 
Here they are bound down by an anular hga 
ment given off from the tendon of the fibular 
is tertius and attached laterally to the distal 
end of the calcaneus The tendons gradually 
diverge as they descend the metatarsus The 
central one divides at the distal end of the 
metatarsus into two branches which end on 
the distal phalanges of the chief (third and 
fourth) digits This tendon is joined before 
bifurcating by the tendon of the extensor 
digitorum brevis The medial tendon ends 
on the middle and distal phalanges of the 
medial chief (third) digit It receives a branch 
from the interosseus at the distal end of the 
proximal phalanx and may detach a tendon to 
the second digit The lateral tendon is smaller 
Its branches end on the distal phalanges of 
the accessory (second and fifth) digits and 
on the lateral chief (fourth digit) there may 
be a branch to the third digit, and the branch 
for the fourth may go to the corresponding 
branch of the central tendon Other van 
ations occur 

The synovial sheath for tbe tendons of the extensor dig! 
torum longus and fibularis tertius at the hock extends 
about 1 cm proximal to the proximal extensor retinaculum 
and about 1 to 3 cm distal to the distal extensor retlnacu 
Iiini in a large adult 

The extensor digitorum lateralis lies on the 
lateral face of the leg caudal to the fibulans 
longus It anses from the lateral surface of 


The extensor digiti I (hallucis) longus is a 
small, fusiform muscle which is covered by 
the extensor digitorum longus and fibularj S 
longus It anses from the proximal end of 
the fibula and its delicate tendon descends at 
first under that of the fibulans tertius, in 
clmes medially at the hock, and ends on the 
medial accessory (second) digit 
The extensor digitorum brevis is a well 
developed muscle which lies on the dorsal 
face of the distal part of the tarsus and on the 
chief metatarsal bones It anses from the 
neck of the talus and the body of the calcan- 
eus and is partially divided into three parts 
The tendon of the superficial part joins that 
of the extensor digitorum longus for the chief 
digits The deep part has two tendons whi<;h 
join those of the extensor digitorum longus 
for the accessory digits 
The gastrocnemius has short but wide aud 
thick heads The lateral one is the larger and 
is united with the flexor digitorum supt»r- 
ficiahs to the distal third of the leg The te' n 
don forms a groove for the superficial digital 
flexor tendon proximal to the hock and i s 
inserted chiefly into the prominences on each 
side of the notch of the calcaneal tuber 
The soleus is thick and wide and blends 
with the lateral head of the gastrocnemius 
It arises from the lateral epicondyle of the 
femur and the deep fascia at the stifle Its 
tendon joins that of the gastrocnemius 
The pophteus presents nothing remarkable 
The flexor digitorum superficiahs has a 
belly of considerable size It anses with the 
lateral head of the gastrocnemius, with which 
it is fused to the distal third of the leg Th e 
tendon is almost entirely enclosed by the 
twist of the gastrocnemius in the distal p^rt 



39 -PORCINE MYOLOGY 


1267 


of the leg. At the calcaneal tuber it is thick 
and largely cartilaginous, and is molded on 
the groove and ridges of the bone. It is at- 
tached by a strong band to each side of the 
calcaneal tuber. A large bursa under the ten- 
don extends proximally in the groove formed 
by the gastrocnemius almost to the muscular 
part and distally to the middle of the calcan- 
eus. The tendon divides distally into two 
branches which go to the chief digits It also 
detaches from its plantar surface two bands 
which join the' fascia of the accessory digits. 

The flexor digitorum profundus presents 
three distinct heads. (1) The tibialis caudalis 
is the smallest. It has a fusiform belly in the 
proximal half of the leg and arises from the 
grooved caudal surface of the fibula. The 
tendon joins that of the flexor digiti I longus 
at the distal end of the leg. (2) The flexor 
digitorum longus is much larger and has a 
fusiform, pennate belly which extends ob- 
liquely across the proximal two-thirds of the 
leg. It arises from the proximal end of the 
fibula, the popliteal line, the middle third of 
the medial part of the caudal surface of the 
tibia and the intermuscular septum between 
this muscle and the flexor digiti I longus. The 
tendon (which has a synovial sheath) de- 
scends in a groove caudal to the medial mal- 
leolus, bound down by the anular ligament, 
inclines laterally on the joint capsule and 
joins the tendon of the flexor digiti I longus. 
(3) Tlie flexor digiti I longus has a large fusi- 


form belly which extends almost to the dis- 
tal end of the leg. It arises from the greater 
part of the caudal surface of the tibia, the 
medial surface and caudal border of the 
fibula, and the interosseous membrane. The 
tendon descends in the tarsal canal, receiving 
the tendons of the other heads, and ends like 
the corresponding one of the forelimb. The 
tarsal synovial sheath begins at the distal 
end of the muscular part and extends to the 
middle of the metatarsus. 

The lumbricales are absent, but there are 
fourinterossei. Rudimentary adductors of the 
second and fifth digits may be found. 


BIBLIOGRAPHY 


Ellenberger, W 1908 Lelsering'a Atlas of the Anatomy ot the Hone 
and the Other Domestic Animals. 2nd cd. Chicago, Alexander 
Eger 

Exner, W 1963 Tendon sheaths and synovial bursae In the limbs of 
pig Wies Z. Humboldt Unlv 12 811-891 

Getty, R 1964 Atlas for Applied Veterinary Anatomy 2nd ed. Ames, 
Iowa State University Press 

Getty, R and N G Choshal 1967 Applied anatomy of the sacro- 
coccygeal region of the pig as related to tall bleeding Vet Med./ 
Small Anim Clinic 62 361-367 

Codlnho, H P , and R Getty 1968. Innervation of the ear muscles 
and associated structures in the pig Arq Esc Vet 20 15-19 

Heinze, W 1961 Anatomical and functional aspects of the muscles 
of mastication of the pig Anat Anz 109 269-291. 

Simic.V 1957 EigenschaftenundUnterschlededesMomohyoIdeus 
ties Menshen tind der Haussaugeticre. Verhandlungen Anat 
Cestallsehaft der 54 Vemmmlung in Freiburg, Br vom 22, bis 
25 September. 1957, pp 366-375 

Sisson. S 1910 A Text book of Veterinary Anatomy Philadelphia, 
W B Saunders Company 



CHAPTER 


40 


PORCINE 

DIGESTIVE 

SYSTEM 

by S. Sisson 

(with Teeth by L. E. St Clair) 


MOUTH 

The oral cavity is relatively tong, the spe 
cific length is influenced by the breed The 
nma on) is extensive, the angles of the mouth 
being situated far caudad The upper lip is 
thick and short and is blended with the snout, 
the lower lip is small and pointed Both lips 
are hairy and bear sinus hairs at their margins 
The part of the upper lip rostral to the in- 
cisor teeth is void of hair The Ups are not 
very motile The labial glands are few and 
small 


CHEEKS 

The mucous membrane of the cheeks 
(buccac) is smooth The buccal glands are 
compactly arranged in two rows opposite the 
cheek teeth (Fig 40-1) They extend from the 
angle of the lips to the masseter muscle, which 
covers them in part They send numerous 
excretory ducts into the buccal vestibule 
The parotid duct opens opposite the fourth 
or fifth cheek tooth 


HARO PAIATE 

The hard palate ( palatum durum ) is Jong 
and narrow, it is marked by a median furrow, 
on each side of which are 20 or more ndges 
(Fig. 40-2) On its rostral part there is a long 
prominence, the incisive papilla, at the cau 
dal part of which the incisive (nasopalatine) 
jlucts open There is a round prominence 
rostral to the first pair of incisors 


TONGUE 

The tongue (lingua) Is long and narrow 
and the apex is thin (Fig 40-3) Two or three 
vallate papillae are present The fungiform 
papillae are small and are most numerous 
laterally The filiform papillae are soft and 
very small. On the root there are soft, Jong, 
pointed papillae, directed caudally Foliate 
papillae are also present 
There is a well marked median glosso- 
epiglottic fold, on either side of which is a 
depression (vallecula epiglottica') The frenu- 
lum linguae is double 

In the prefrenular portion of the floor of 
the mouth caudal to the middle incisor teeth 
are the orobasal organs, the size of a pin- 
head. Lateral to the attachment of the lingual 
frenulum are the very small sublingual car- 
uncles 


TEETH (DENTES)* 

by L. E. St Clair 


Permanent Teeth 

The formula of the permanent teeth of 
the pig is 


2 (IfCfPi A!)) = 44 


’Other fieurt-i illustrating the teeth are to be ftnjmJ In 
Chapter 37 


1268 



40 -PORCINE DIGESTIVE SYSTEM 


1269 



FIGURE 40-1 Superficial glands of head of pig 


a Parotid gland a , a" cervical and mandibular angles of a b 
masseter f parotid and f lateral retropharyngeal lymph nodes 
which is concealed (From EUenberger and Baum 1908 ) 


ventral and c dorsal buccal glands d labial glands e 
g dotted line indicating outline of mandibular gland 


T* 16 pig has the full number of teeth pos 
sessed by the primitive placental mammal 
Incisor teeth The incisor areas are 
shaped so that the medial teeth he in a 
plane decidedly rostral to the lateral teeth 
The vestibular (labial) surface of the crown 
l^s an extensive covering of enamel, but 
the lingual surface has enamel on its mar 
Sins only Cementum covers the portions 
not possessing enamel The upper incisors are 
separated from each other by spaces and 
u m canine by a large interval Although 
mere is no distinct neck, the crown, which is 
broad, tapers as it becomes the root The re 
auction in size continues through the short, 
round root The teeth decrease decidedly m 
size and curvature from 1 to 3 The convex 
*ty is on the vestibular surfaces of both the 
orown and root The crown of the third in 
oisor may be slightly trituberculate The low- 
er incisors lie in a horizontal plane and are 
i? S u , l °Sether They are rod like and only 
slightly curved The intermediate tooth is 
slightly larger than the central and much 
larger than the comer incisor The third in 
cisoris the only one with a neck. The roots are 


long, round in cross section and deeply im- 
planted in the jaw 

Canine teeth (tusks) The canine 
tooth is especially well developed m the 
male and projects from the mouth It is open 
rooted and, thus, is replenished as it pushes 
from the alveolus The crown of the upper 
canine is conical and curves laterally, dor 
sally and slightly caudally The lower canine 
is long, pointed, and three sided It curves lat- 
erally and caudally rostral to the upper one so 
that friction between the two keeps them 
sharp and pointed The convex surface is 
covered with enamel, the concave with ce 
mentum (Fig 40-4) 

Cheek teeth The cheek teeth increase 
in size from rostral to caudal They have 
bunodont crowns which are short, forming a 
neck near the roots The occlusal (table) 
surfaces of the molars consist of complex 
crushing mounds, while those of the pre- 
molars are of the cutting type The first pre 
molar in each jaw is small and simple The 
lower one lies just caudal to the canine 
tooth The diastema occurs between the 
canine and th$ first premolar in the upper 



1270 


PORCINE 


jaw but between the first and second pre 
molars in the lower jaw In the upper jaw the 
first and second premolars possess two roots 
the third three and the fourth five The 
molars have six roots In the lower jaw the 
first premolar has one root the second and 
third two and the fourth three The first 
and second molars have four roots the third 
molar has five (Figs 40-5 6 and 7) Enamel 
covers the crown and cementum the roots 


DeciduousTeeth 

The formula for the deciduous teeth is 
2 (DiJ Dcf- Dpi) * 28 

The deciduous teeth resemble very closely 
their corresponding members of the perman 
ent set However Dp* is more bunodont 
than P 4 and Dp 4 has three cusp units The up 
per deciduous premolars have two three 
and four roots respectively The lower 
deciduous premolars have two roots except 



FIGURE 40-2 Hard palate of jourtg pig 

1 Incisive papilla 2, openings of Inc s ve duct 3 pa la 
tine raphe a, incisor teeth "b canine too h c premolar 
teeth d. molar teeth. 



FIGURE 40-3 Tongue of pig 


1 Apex 2 dorsum 3 root a orifices of ducts of lingual 
glands b pap Uae of root c vallate papilla (not really to 
d* met as In figure) d foliate papilla e fungiform papil 
7 * * 'epiglottis (pulled back) g, median glossoepiglottic 
fold. (From Ellenberger and Baum 1908 ) 


the last one which has five (Figs 40 8 
and 9) 


Eruption of Teeth 

The deciduous comer incisor and the ca 
tune are present at birth The deciduous pre 
molars and the central incisor erupt during 
the first month The intermediate deciduous 
inc sor appears at two months The first pre 
molar and first molar appear at five months 
the comer incisor and canine erupt at about 
nine months The central incisor and second 
molar erupt at about 12 months The other 
premblars are in by 15 months and the last 
r a °.Sf,a nd intermediat e incisor by 18 months 
Latitude in tune is shown m Table 40-1 


Cementum Enamel Dent 



FIGURE 40-1 Cross section of lower csn.ne loolh 
of pig 

c Pulp cavity 



FIGURE 40-5. Skull of pig 
about a year and a half old, 
sculptured to show the embed- 
ded parts of the teeth. 

C, Canine; 1 1-3, incisors; P 1-4. 
premolars; M 1-3, molars. The 
third molar has not erupted and 
its roots are not yet formed. 


40— PORCINE DIGESTIVE SYSTEM . 







Figure 40-8. Upper teeth of pig in skull; young FKSUItE I0-‘J. loser teeth of pig in mandible; 
animal. deciduous. young animal. deciduous. 

DC Mnclsors, Dc, canine. Dp*' 4 , premolars Di, . incisors, Dc. canine. Dp, premolars 


TABLE 40-1. Eruption Times of the 
Teeth of the Pic 


Tooth 

Eruption 

Chance 

1 1 

2 lo 4 weeks 

12 months 

I 2 

(upper, 2 lo 3 mouths 
[lower. J V« to 2 months 

16 to 20 months 

l 3 

before birth 

8 to 10 months 

C 

before birth 

9 to 10 months 

P 1 

5 months 


P 2 

5 to 7 weeks 


P 3 

{upper, 4 lo 8 days | 

[lower, 2 to 4 weeks 

| 12 to 15 months 

P 4 

(upper, 4 lo 8 days , 

Power. 2 to 4 weeks 



4 to 6 months 



8 to 12 months 


M 3 

18 to 20 months 



'by S. Sisson 

SALIVARY GLANDS 

PAROTID GlAND 

The parotid gland is large and distinctly 
triangular (Fig. 40-1). It extends very little 


onto the masseter muscle, and its dorsal 
angle does not quite reach the base of the ear. 
It is pale in color and is embedded in Fat in an- 
imals in good condition. On its deep face are 
several large parotid lymph nodes, some of 
which are only partially covered by the paro- 
tid The parotid duct arises on the deep face, 
has a course similar to that of the ox and per- 
forates the cheek opposite the fourth or fifth 
upper cheek tooth Small accessory paro- 
tid glands may be found along the course of 
the duct. 


MANDIBU1AR GlAND 

The mandibular gland is small, reddish in 
color and oval in outline; it is covered by the 
parotid (Fig. 40-1). Its superficial face is 
convex and is marked by rounded prom- 
inences (Fig. 40-10). From its deep face a 
narrow process extends rostrad about 5.0 to 
7.5 cm beneath the mylohyoideus muscle 



40 -PORCINE DIGESTPV E SYSTEM 


1273 



along with the duct The latter opens near the 
frenulum linguae, but there is no papilla 


SlIBUNGUAl GLAND 

The sublingual gland has an arrangement 
similar to that of the ox The caudal part 
(tnonostomatic sublingual gland) is reddish 
yellow m color and is about 5 cm long and 1 
cm wide, its caudal end is in relation to the 
mandibular gland and Us duct All or most of 
the ducts from the caudal part unite to form 
the major sublutgual duct, which opens near 
the mandibular duct The rostral pirt (pol>- 
stomatic sublingual gland) is much larger, 
being 5 to 7 cm long and about twice the 
"Idtli and thickness of the caudal part 
Eight or ten minor sublingual ducts com ey 
the secretion from' the rostral part through 
the floor of the mouth (fig 40-10) 


PHARYNX 

The pharynx, which is long and narrow, 
extends to the lc\el of the second cervical 
vertebra It is divided into the naso and oro- 
pharynx, which are connected by the narrow 
intraphary ngcal opening, tlie soft palate and 
the palatopharyngeal arch 


SOFT PALATE 

The sort palate (palatum malic ) is very 
thick, us length in an animal of medium 
size is about 5 cm, its direction almost con- 
tinues that of the hard palate, i c , it is nearly 
horizontal It extends to the middle of the 
oral sui face of the epiglottis It has in many 
casts a small median prolongation termed 
the uvula The oral surface presents a median 
furrow, on either side of which is an oval 



1274 



FIGURE 40-11 Sagittal section of pharyneal 
region of pig partly schematic 

1 Palatine bone 2 sphenoid bone 2 sphenoidal sinus 
2 occipital bone 3 epiglottis with 3 oral and 3 
laryngeal mucous membrane 4 arytenoid cartilage 5 
thyroid cartilage 6 root of tongue 7 mouth cavity 8 
Isthmus faucium 9 hard palate 10 nasal septum II 
ventral muscles of head a. soft palate a free edge of a 
b dorsal wall of pharynx c fornix of pharynx d cavity of 
larynx e g nasopharynx f oropharynx h palato- 
pharyngeal arch of soft palate 1 dotted line indicating lat 
era! boundary beCnxtn naval cavity and pharynx V. 
laryngeal vestibule 1 esophageal opening m auditory or 
ifice n pharyngeal diverticulum o choana (From Ellen 
berger and Baum 1908 > 


PORCINE 

derived from Ihe pihtinus and palalophar 
tp. cus muscles The fornix of the p!nr>nx Is 
divided bs a median fold of mucous mem 
brant which is a direct continuation of ih«- 
nasal septum On either side of tills Is an in 
fundlbulum into which the auditory tube 
opens 

ESOPHAGUS 

The esophagus originates from the esoph 
a geal vestibule or the pharynx at the level 
of the nuchal margin of the caudal plnrjn 
peal constrictors The csoplngus Is short and 
nearly straiRht It has (accordmR to Rubeh. 
cited by Sisson 1910) a potential caliber In 
the adult of nearly 7 cm at either end and 
about 4 0. cm in Its middle part. The esophi 
Real hiatus is a lonR slit In the riRht cru s of 
the diaphragm, and the terminal part of 
the esophagus which lies In It is flattened 
transversely The muscular coat is striated, 
except near the cardia where the deep 
part is smooth There are numerous tu 
buloalv eolar glands in the cranial half of 
the tube further caudad they occur in dc 
cr casing numbers Many lymph nodules and 
much lymphoid tlssueare present 


raised area marked by numerous crypts 
these elevations are the tonsils Tonsillar tis 
sue also occurs in the lateral walls of the 
isthmus faucium and the root of the tongue 
The isthmus faucium is short like the soft 
palate Its floor, the base oF the tongue, drops 
off steeply against the base of the epiglot 
tis whereas its tooF is represented by the 
almost horizontally located soft palate In 
almost all cases the epiglottis is found pro- 
jecting under the soft palate into the isthmus 
faucium on post mortem examination The 
especially high laryngeal prominence has 
conspicuously deep piriform recesses which 
he lateral to it in the adjacent laryngeal part 
of the pharynx. It is assumed that food is 
able to flow past the enclosed larynx through 
these deep grooves and that the pig is able to 
breathe and swallow at the same time The 
comiculate cartilages of the arytenoid car 
tilage and the palatopharyngeal arch he in 
the same transverse plane which at the same 
time forms the oral boundary of the adjacent 
esophageal vestibule The latter goes over 
into the esophagus without a limen pharyn 
goesophageum (Nickel et al 1960) 

The pharynx presents in its caudal part a 
median cul de-sac about 3 to4 cm long, which 
is situated between the rectus capitis ven 
trails and the ongin of the esophagus this is 
termed the pharyngeal diverticulum (Fig 
40-11) Its ventral margin is formed by the 
junction of the palatopharyngeal arch of the 
soft palate, which contains muscular tissue 


STOMACH 

The stomach (tentriculus (gasterj) is large, 
its average capacity is about 5 7 to 80 1 
When full its long axis is transverse and its 
greater curvature extends caudally on the 
floor of the abdomen a little farther than a 
point midway between the xiphoid cartilage 
and the umbilicus The left part is large and 



FIGURE 40-12 Stomach of pig parietal surface 

The organ contained a rather small amount of Jn?esta 
and hence i* somewhat contracted 



1275 


40— I'ORCINE DIGESTIVE SVSTEM 



l I (JURE 40-13 Stomach of pig, ' isceral surface 
Organ was fixed in situ and is somewhat contracted 


rounded, while the nght part (pyloric part) 
is small and bends sharply dorsally to join 
the small intestine The parietal surface 
(Fig 40-12) faces chiefly cramad and is re 
lated to the liver and diaphragm The vis 
ceral surface (Fig 40-13) faces chiefly cau 
dad and is related to the intestine, greater 
omentum, mesentery and pancreas The 
greater curvature is related to the diaphragm, 
spleen, liver and abdominal floor The pyloric 


end lies against the right lateral lobe of the liv- 
er, about opposite to the middle of the thir- 
teenth intercostal space The left extremity is 
ventral to the dorsal part of the thirteenth nb 
and intercostal space and is related to the 
dorsal end of the spleen and the left extrem 
lty of the pancreas, it presents a flattened 
conical blind pouch, the diverticulum, the 
apex of which projects caudally The esoph- 
agus joins the stomach very obliquely just 
to the left of the median plane, and about 
6 to 10 cm ventral to the thirteenth thoracic 
vertebra. The cardiac opening is slit like 
and is bounded dorsally and to the left by a 
fold which contains a thickening of the in 
temal oblique layer of the muscular coat 
The opening into the diverticulum is situated 
above and a little to the left of the cardia 
(Fig 40-14), it is oval and is bounded by a 
thick fold which contains spirally arranged 
muscular fibers 

The mucous membrane may be divided into 
four regions (Figs 40-15 and 16) Over * 
quadrilateral area around the cardia (which 
extends to the margin of the diverticulum on 
the left) it is esophageal m character, gland 
less, and presents a number of folds, the 
pro\entncular part A sharp line of demarca- 
tion separates this from the rest of the mu 
cous membrane, which is soft and glandular 
The cardiac gland region is pale gray in color 
and thin (ca 0 5 to 1 0 mm), it extends about 
to the middle of the stomach The fundus 
gland region is readily distinguished by its 


FIGURE 40-14 Cross sec 
lion of pig, caudal Mew 

Section is cut through caudal 
end of the thirteenth thoracic ver 
tebra 1 Aorta (thoracic duct to 
upper right or Aorta) 2 2 left 
and right crura of diaphragm 3 
caudal vena cava 4 portal v 5 
hepatic lymph nodes 6 hepatic 
a 7 gastric branch S common 
bile duct 9 diverticulum of stom 
ach 10 gallbladder C 11 cartl 
!agc of eleventh rib IL left 
iung R 12 R 13 ribs 12 and 13 
R i- right lung arrow points to 
cardia X1H thirteenth thoracic 
vertebra 




PORCINE 


1276 

thickness (ca 3 mm) and Us brownish red 
mottled appearance * The pjloric region is 
pale thinner than the preceding and presents 
a number of irregular folds * At the pylorus 
a remarkable prominence torus pyloncusi 
projects from the wall of the lesser curvature 
and diminishes considerably tht size of the 
orifice (Fig 40-17) It is about 3 to 4 cm long 
and nearly 1 cm high Sometimes it is a 
grooved ndge in other cases it has the form of 
a rounded eminence attached by a pedicle to 
the wall According to Bal and Ghoshal 
(1972) it is nchly glandular with lobules of 
tubular mucous glands in its lamina propna 
Large vascular spaces are seen at the base of 
the lamina propna. There are two distinct 
muscle layers— an internal fibromuscular lay 
er and an external muscular layer with an 
inconstant layer of adipose tissue between 
The external muscle layer forms the pedicle 
The pylonc torus plays both an active and pas 
sive role in completely closing the pvlonc 
orifice the torus dovetails uetween the free 
ends of the semilunar sphincter pylon 
muscle thus acting like a plug The arrange 
ment of the muscular coat of the stomach is 
shown in Figures 40-17 and 18 


SMALL INTESTINE 

The small inttwtine (tntestmum tenus ) 
is 15 to 20 m long 


tM cto J cop c examination chow, that these regions are 
not shatjly marked off from each other instead there are 
intermediate rones In which glands of both the adjacent 
regions are present and also glands of imermediate his- 
tological character 



FIGURE 40-15 Diagram of zone* of mucous 
membrane of stomach of pig. 


Du ertiadum 



HGURF 40-16 Frontal section of stomach of pig. 


DUODENUM 

The mesentery of about the first GO cm is 
5 to G cm long this part may be termed 
duodenum It anses on the right side in the 
region of the tenth to twelfth Intercostal 
spaces from the pylorus The cranial part of 
the duodenum turns sharplj medially on the 
visceral surface of the liver to the nght of 
the portal fissure The descending part passes 
caudally in relation to the medial part of the 
nght kidney dorsally and the colon ventrally, 
and about the middle of the sublumbar region 
turns across the median plane and runs (as 
uie ascending part) cramally to be continued 
by the mesentenc part (jejunum and ileum) of 
the small intestine The nght end of the 
pancreas is attached to the cranial part and 
here the pancreatic duct opens into the bowel 


JEJUNUM AND UEUM 

The remainder of the bowel has a mesentery 
about 15 to 20 cm long which is thick and 
contains a quantity of fat and numerous large 

nf ?l eS a ,! its 1001 the root 1S attached 

sobjumbar region caudal to the stom 

fh? b e ? dS herC Wllh the mesentery of 
the large intestine The mesentenc part of 
the small intestine is arranged in close coils 
and l.es mainly dorsal to the colon and cecum, 
from the stomach to the pelvis many coils 

narfSr.l 51 he n § h ! flal * and °n the caudal 
part of the floor of the abdomen (Fig 40-19) 

as e t« P ?X ng °V he co J nmon We duct is about 
7,” !° 5 ° C . W J r ° m , the Py lorus an d that of 
the pancreatic duct about 10 to 12 cm beyond 
it Aggregated lymph nodules or Pejer’s 



40 - 1 ’OKCINE digestive system 


1277 


d p 




f r\ * V *N 

J WHS 


*5S? gGc a 




•< &F- 

'/, >*U 



•mm 


i, VfKj 


. , PIGUKE 40-18 Stomach of pig fro* wh.ch the 

TIGURE 40-17 Everted stomach of ptg from which Dhunc „ erous coa t has been removed 

themucousmembranehasbeenremoved fibers c external oblique 

D Duodenum D1 diverticulum O esophagus a a a * Wc h connect branches of cjudiac loop f Wd at entran 
felutTpM Ellenberger and Daum ,908> 


PIGURE ^®~19 Abdominal viscera of 
P»B ventral view 

B T ^ Kreaie . r om enium has been removed 
Ph mi f~2, bladder G gallbladder X » 
colKnPt Se Arrows Indicate course of 
i colon The spleen was contracted 







f/'. *") A 

r^M) 


wp^ 

U'.VaA* 




„t?35 si-can 




PORCINE 


1276 

thickness (ca 3 mm) and its brownish red 
mottled appearance* The pyloric region is 
pale thinner than the preceding and presents 
a number of irregular folds t At the pylorus 
a remarkable prominence i torus pyloncus) 
projects from the wall of the lesser curvature 
and diminishes considerably the size of the 
orifice (Fig 40 17) It is about 3 to 4 cm long 
and nearly 1 cm high Sometimes it is a 
grooved ridge in other cases it has the form of 
a rounded eminence attached by a pedicle to 
the wall According to Bal and Ghoshal 
(1972) it is richly glandular with lobules of 
tubular mucous glands in its lamina propna 
Large vascular spaces are seen at the base of 
the lamina propna. There are two distinct 
muscle layers -an internal fibromuscular lay 
er and an external muscular layer with an 
inconstant layer of adipose tissue between 
The external muscle layer forms the pedicle 
The pylonc torus plays both an activ e and pas 
sive role in completely closing the pvlonc 
onfice the torus dovetails uetween the free 
ends of the semilunar sphincter pylon 
muscle thus acting like a plug The arrange 
ment of the muscular coat of the stomach is 
shown in Figures 40-17 and 18 


SMALL INTESTINE 


The small intestine (intesttnum tenus ) 
is 15 to 20 m long 


I'!! ‘S. n0 ," d «>"* "El"" <1«> not 

‘ h ' 

t Microscopic exam nation shows that these regions are 
not sharply marked off from each other instead there are 
intermediate zones in which glands of both the adjacent 
regions are present and also glands of ittjermedtate his 
tological character 



FIGURE 40-15 Diagram of zones of mucous 
membrane of stomach of pi» 


Dnerticulum 



FIGURE 40-16 Frontal section of stomach of pig 


DUODENUM 

The mesentery of about the first 60 cm is 
5 to 6 cm long this part may be termed 
duodenum It arises on the right side in the 
region of the tenth to twelfth intercostal 
spaces from the pylorus The cranial part of 
the duodenum turns sharply medially on the 
visceral surface of the liver to the nght of 
the portal fissure The descending part passes 
caudally in relation to the medial part of the 
right kidney dorsaUy and the colon \entrally, 
and about the middle of the sublumbar region 
turns across the median plane and runs (as 
the ascending part) cranially to be continued 
by the mesenteric part (jejunum and ileum) of 
the small intestine The nght end of the 
pancreas is attached to the cranial part, and 
here the pancreatic duct opens into the bowel 


JEJUNUM AND IIEUM 

The remainder of the bowel has a mesentery 
about 15 to 20 cm long which is thick and 
contains a quantity of fat and numerou. large 
ymph nodes at its root, the root is attached 
in the sublumbar region caudal to the slom 
i a ." d b ends 1,ere ' vlth ,he mesentery of 
the large intestine The mesenteric part of 
the small intestine is arranged in close coils 
and lies mainl> dorsal to the colon and cecum 
from the stomach to the pelvis many cods’ 
" E1 “ t nght flank and on the caudal 
part of the floor of the abdomen (Fig 40-19) 
The opening of the common bile duct is nboul 
25 to 5 0 cm from the pylorus and that of 
the pancrcahc duct about 10 to 12 cm beyond 
it Aggregated lymph nodules or Peyer’s 



40 -POItCINE digestive system 


1277 




ifTii 




\ ^ 


FIGURE 40-17. Everted stomach of pig, from which 
the mucous membrane has been removed. 






FtrURE 40-18. Stomach of pig, from " hich the 
FIGURE cMt has boen rem „vcd. 

. innvitudlnal fibers b. cccular fiber., c. external oblique 


me mucous memnrane nas uet:« circular fibers, c, extei 

E, Duodenum, Di, diverticulum, O, eS0 P h f BUS ’?’ r a h ’«\vhi C h connect branches of Q “f? iac lo ° P ’ f ° ld ** 
fibers, c’, internal oblique fibers, c", cardiac loop, d, fibers £n en berger and Baum, 1908 ) 
diverticulum, p, pylonc sphincter, p . torus pyloncus (From Elienoerg 





FIGURE 40-19. Abdominal viscera of 
p»g; ventral view. 

B^i*M Rteat , r ome ntum has been removed 
Pho!dS Wadder - G, gallbladder. X. xi 
CoUsnf 1 86 Arrows indicate course of 
colon The spleen was contracted 




f CL 


' 4 J . ^ 



Uv °.. ^ 


•!&': )■ ■} 

/• S' 0 !v' 0 


v 9 :&-< 



ftt 

5 






J 




40-PORC1NE DK.rSTHE S'! STEM 


1279 


FIGURE 40-22 Cecum and 
colon of pig left central we\\ 

1 Apex of spiral coil of colon 2 
apex of cecum 



is continued at the pelvic inlet by the rectum 
This terminal part is closely attached by a 
short mesentery to the sublumbar region 
The ascending colon has two bands and 
two series of sacculations which however, 
gradually disappear in the centrifugal part 
The solitary nodules are numerous and ap 
pear as round prominences 2 to 3 mm in 
diameter, often with a crater like depression 
There are often aggregated lymph nodules 
or Pej er’s patches in the first part of the colon 



FIf.tIRF 40-23 Ileal opening of pi g 


1 Ileal opening 2. Ueal frenutum 


RECTUM 

The rectum is the continuation of the de 
scending colon It is usually surrounded by a 
quantity of fat 

ANUS 

The anus is short The following muscles 
are lelated to the anus sphincter am intemus 
a ring of smooth muscle surrounding the 
anus a sphincter am externus and the levator 
am 

The intestine is about fifteen times the 
length of the body 

PANCREAS 

The pancreas extends across the dorsal 
wall of the abdominal cavity caudal to the 
stomach It is tnradiate or triangular The 
right lobe is attached to the first cur\e (fit x 
xtra portahs) of the duodenum and here the 
duct passes to the bowel The left lobe is re 
lated to the left extremity of the stomach 
the dorsal end of the spleen and the cranial 
pole of the left kidney The middle portion 
is related to the portal vein and the root of 
the mesentery The pancreatic duct passes 
from the nght lobe directly through the 
duodenal wall opening about 10 to 12 cm 
from the pylorus The interlobular tissue 
usually contains a good deal of fat 



1280 


PORCINE 


IIVER 

The liver (hepar) is relaUvely large, its 
average weight in the adult being about 1 5 to 
2 0 kg It is thick centrally, but the circum 
ference is thin It is divided by three deep 
interlobar incisures into four principal lobes— 
right lateral, right medial, left medial and 
left lateral, the last of these is usually con 
siderably the largest On the dorsal part of the 
right lateral lobe is the caudate lobe, which 
is clearly marked off by a fissure and is often 
partially subdivided by a secondary fissure 
The caudate process projects to the right and 
dorsally There is no papillary process The 
quadrate lobe lies ventral to the portal fissure 
and to the left of the gallbladder and cystic 
duct The diaphragmatic (parietal) surface is 
extremely convex, m conformity with the 
curvature of the diaphragm to which it is 
chiefly related* (Fig 40-24) A small part of 
the surface is m contact with the abdominal 
floor in the xiphoid region and ventral to the 
right costal arch Its most cranial part reaches 


•The description here given Is based on the appearance 
of the organ as hardened in titu which differs radically 
from that of the soft organ. It also differs much In shape 
In young and adult subjects 


to a transverse plane through the ventral 
part of the sixth nb or intercostal space The 
visceral surface is deeply concave, most of 
it is related to the stomach, for which there is 
a correspondingly large and deep gastric 
impression There may be a duodenal impres- 
sion on the dorsal part of the nght lateral 
lobe, but no renal impression exists, as the 
right kidney does not touch the liver The 
fossa for the gallbladder (fossa vesicae 
felleae) is mainly on the nght medial lobe, 
but also in part on the adjacent surface of the 
left medial lobe The caudal vena cava enters 
the dorsal border of the caudate lobe and soon 
becomes entirely embedded in the gland 
substance, emerging only at its passage 
through the diaphragm (Fig 40-25) The 
esophageal impression is large and is occu- 
pied mainly by the large nght crus of the 
diaphragm The nght lateral border extends 
caudally to the dorsal part of the last inter- 
costal space The left lateral border is chiefly 
opposite the ninth intercostal space and 
tenth nb The ventral border lies on the ab- 
dominal floor a short distance (ca 3 to 5 cm) 
caudal to the xiphoid cartilage 
The coronary ligament resembles that of 
the horse The falciform ligament is very short 
or absent in the adult and is attached to the 
diaphragm just ventral to the foramen venae 
cavae The round ligament is present in the 



FIGURE 40-24 Liver or pig, 
parietal surface 


1 1 , Large hepatic w opening Into 
caudal vena cava 2, 2 , coronary Jig 
3 falciform lig. Only a very small 
part of the notch for the round lig be- 
tween the right and left medial lobe* 
is visible above 4 


Left mrdial tobr 



40- PORCINE DIGESTIVE SYSTEM 


1281 


FIGURE 40-25 Liver of pig, Msceral 
surface 

The peritoneum and fat have been re 
moved from the vicinity of the portal fis 
sure 1, Cystic duct 2 common bile duct 3 
lymph nodes 



Left medial lobe Gallbladder 


young subject Neither triangular nor caudate 
ligaments are present 

Owing to the large amount of interlobular 
tissue, the lobules are mapped out sharply, 
they are polyhedral in form and are 1 0 to 
2 5 mm in diameter For the same reason the 
gland is much less friable than that of the oth 
er animals, from which it is easily distin 
guished 


GALLBLADDER 

The gallbladder (vested fellea) is attached 
in the fossa for the gallbladder between the 
quadrate and right medial lobes of the liver 
Its fundus does not reach to the ventral bor- 
der The cystic duct joins the hepatic duct at 
an acute angle immediately after the emer- 
gence of the latter from the portal fissure to 



I- IGUItE 40-26 Projection of \fscera of pi* on bodj wall, left side 
D b. Bulbourethral Eland D costal line of diaphragm P, penis U ureter V S , \ eslculur gland. 



1282 


PORCINE 



FIGURE 40-27 Projection of viscera of pig on bod) wall, right side 

D Costal line of diaphragm O ovary The pancreas and duodenum are not In contact with the flank, as would naturally 
be Inferred from this figure but are situated more medially and are covered laterally by small Intestine 


form the bile duct The common bile duct 
( ductus clioledochus) opens at the papilla 
duodem about 2 5 to 5 0 cm from the py 
lores an ampulla may be formed 



lie mammal* 1 Problem portion, review of literature maleri 
•l and method* *tomach mu*ele* of the *»fne Anat Ant, 
129 84 104 

Koppan*. H S and R Catty 1970 HUtomorpholoslcal *tudle* of 
the porcine parotid tland a* related to aje B rth to early adult 
hood Growth. 34 321-340 

Koppanc H S and R. Getty 1970 Hittomorphologieal studies In the 
porcine parotid tland a* related lo a*e- Maturity to senescence 
J C erotic 25 364 37a 

Nickel R A Schummer and E Seiferle 1960 Lehrbuch tier Anat 
omiederllauttlere Band IL Berlin. Paul Parry 

Preu** F and II Lange 1970 Double-spiral colon of the pif. ZbL 
Vet Med AI7 603-17 

S icon S 1910 A Text book of Veterinary Anatomy Philadelphia, 
W B Saunders Company 

Slo»* M W 1954 The microteoplc anatomy of (he diseitive tract of 
Sul icrdfadomeitica Am J vet. Re* 15 578 593. 

St Clair L. E, 1970 Chapter One In H W Dunne fed.) Dlseaiei of 
Swine 3rd ed Ame* Iowa State University Pref*. 

W raver M E- E. B Jump and C F McKean. 1966 The eruption 
pattern of dedduou* teeth tn miniature swine Anat Ree 
154 81 86 

Weaver M E E. B Jump and C F McKean. 1969 The eruption pat 
tern of permanent teeth in miniature twine Arch oral BWL 
14 323-331 

Zlriztchman O E Ackemecht and H Crau 1943. Ellenberger and 
Baum * Handbuch der Versleichenden Analomle der Ha u« tie re 
18th ed Bert n Sprinter Verlag 



CHAPTER ,/j.| 


NOSE AND NOSTRILS 

The nose is embodied within the skeleton of 
the face and extends caudad to about the level 
of the eyes The apex of the nose and the upper 
lip form the snout, or rostrum. The skin of the 
nose, except for that of the apex, is covered by 
hairs The dorsal and lateral walls of the nose 
are bony except for the rostral parts of the lat- 
eral walls, which are cartilaginous The dorsal 
and ventral lateral (parietal) cartilages of the 
nose curve lateroventrad and laterodorsad, 
respectively, and meet to complete the wall, 
on each side, in the angle foijned by the bor- 
der of the nasal bone and the palatine process 
of the Incisive bone (Figs 37-47 and 48) 

The nostrils are two round openings situated 
in the snout, bounded by the medial and lateral 
w ings, or alae, and supported by the underlying 
skeleton 

The skeleton of the snout and nostrils is 
formed as follows The rostral end of the nasal 
septum is modified to form the rostral bone 
(os rostrale) which is shaped like a three 
sided pnsm The apex of the prism ism apposi- 
tion with the nasal septum, with the base of 
the pnsm facing rostrally and underlying the 
skin between the two nostnls (Fig 37-49) 
The dorsal surface has a median groove, while 
the lateral surfaces are concave and converge 
ventrally. The rostral part of each dorsal lat- 
eral cartilage arises from the dorsal surface of 
the rostral bone and curves dorsally, laterally, 
and ventrally to support the dorsal part of the 
nostril. The rostral part is separated from the 
main part of the dorsal lateral cartilage by a 
deep fissure Projecting laterodorsad from the 
ventral part of the rostral bone is the awl- 


PORCINE 

RESPIRATORY 

SYSTEM* 

by W. C. D. Hare 


shaped lateral accessory cartilage (Figs 37- 
47 to 49) which supports the lateral wing of 
the nostnl The presence of the rostral bone 
provides the snout with a firm basis for root- 
ing 

The nostnls of the pig cannot be dilated to 
any great extent because of the fairly com 
plete skeletal support 

The thin, sensitive skin covering the snout 
forms the planum rostrale. It cames short, 
bnstly sinus hairs and may be pigmented The 
surface of the skin is divided by shallow 
grooves, or sulci, into small areas called are- 
olae. These surface markings are charactens- 
tic for each individual, and imprints of them 
can be used for Identification purposes Tubu- 
lar serous glands, whose secretions keep the 
surface of the planum rostrale moist, open 
into the depths of the grooves The skin that is 
reflected into the nostnls cames hairs (vibns- 
sae) The philtrum, a median groove dividing 
the upper lip, extends dorsad for a short dis- 
tance on the planum rostrale 

Vessels and nerves The nostnls and the 
surrounding area are supplied mainly by the 
terminal branches of the infraorbital artery, 
together with the terminal branches of the 
greater palatine and sphenopalatine arteries. 
Blood is drained from the area by the infraor- 
bital, palatine, and sphenopalatine veins The 
lymphatic vessels dram into the parotid and 
mandibular lymph nodes Nerve impulses are 
carried from the snout by the infraorbital 
nerves (sensory) and to the muscles of the 


•For general visceral considerations tcrmlrioIoK> and 
embrv ological concepts see details In Cluptrr C ( eneral 
Splanchnotocv 


1283 



1284 

nostrils by branches of the facial nerves 
(motor) 


NASAl CAVITY 


The nasal cautj is relatively long and nar 
row It is divided into nght and left halves by 
the median nasal septum Each nostril leads 
into one half of the nasal cavity The nasal 
septum has an osseous part, a cartilaginous 
part and a membranous part The osseous part 
is composed of the lomer and theperpcndicu 
lar plate of the ethmoid bone The vomer is 
very long and extends as far rostrad as the 
> of the incisiv e bone V entrally it is in con 
with the palatine maxillary and incisive 
bones from the caudal border of the hard pal 
ate to the body of the incisive bone The per 
pendicular plate of the ethmoid bone extends 
as far rostrad as the transverse level of the 
sixth cheek tooth The cartilaginous part of 
the septum consists of a median plate of hya 
line cartilage which extends from the rostral 
border of the perpendicular plate of the eth 
moid bone to the apex of the os rostrale, which 
is embedded in the rostral end of the septum 
In older animals the cartilage becomes ossi 
fied to a variable extent It is related dorsally 
to the nasal bones and ventrally to the vomer 
The dorsal border is expanded on each side to 
form the thin dorsal lateral cartilages (Fig 
41-1) Rostrally the ventral border is expanded 
on cither side to form the ventral lateral carti 
lages (Fig 41-1) On each side in the region 
of the nasoincisive notch the dorsal and ven 
tral lateral cartilages curve toward each other 
and TOstrally complete the skeleton of the 
nasal wall The part of the nasal cavity caudal 
to the level of the fifth or sixth cheek tooth is 
divided completely into dorsal and ventral 
parts bj a horizontal plate (transverse lamina) 
which is formed by the vomer, palatine and 


PORCINE 

ethmoid bones The part of the cavity situated 
dorsal to the horizontal plate is olfactory in 
function and is known as the fundus, while 
the part situated ventral to the lamina is re 
spnatory in function and is known as the naso- 
pharjngeal meatus Each nasopharyngeal 
meatus leads into the nasopharynx through a 
caudal nans or choana Each choana is 
bounded ventrally by the caudal border of the 
palatine process of the palatine bone, laterally 
by the perpendicular plate of the palatine 
bone, and dorsally and medially by the vomer 
and the palatine bone The crest of the vomer 
is covered by mucous membrane which is 
continued caudad as a fold into the roof of the 
nasopharynx This fold of mucous membrane 
forms the membranous part of the nasal sep- 
tum and divides the dorsal part of the naso 
pharynx into two halves 
The greater part of the nasal cavity is occu 
pied by the conchae (turbinate bones) which 
project from the lateral wall almost to the sep 


The dorsal nasal concha is long and narrow 
It extends from the cribriform plate of the 
ethmoid bone to the rostral extremity of the 
nasal bone The fold of mucous membrane 
extending rostrad from the dorsal nasal con 
cha along the dorsal part of the lateral wall 
toward the nostril is called the straight fold 
The ventral nasal concha is shorter and 
broader It extends from the level of the fifth 
cheek tooth to approximately the level of the 
canine tooth The fold of mucous membrane 
extending rostrad from the ventral nasal con 
cha along the lateral wall of the cavity to the 
dorsolateral part of the nostril is called the 
atar fold, It contains the medial accessory car- 
tilage and may also contain a rudimentary 
nasolacrimal duct and orifice The medial ac 
cessory cartilage anses from the rostral end 
of the ventral nasal concha and from the ven 
tral lateral cartilage Extending caudad from 
the alar fold ventral to the ventral nasal con 



FIGURE 41-1 Transverse section of 
nasal cavity of mature pig (schematic), 
caudal view 


■ J, ^ „ iwumnc 1 . vomer 

D hard palate (mucosa) E tendon of Ie vato 
Ubll maxUlaris F maxillary tnei.ure C 
tendon of caninus If tendon of depresso 
labii maxillarts J labial part of orbicular! 
oris „ nasal septum (cartilaginous) a dor 
sal lateral nasal cartilage b ventral la t era 
nasal cartilage c nasolacrimal duct d va 
meronasal organ (mucosa) e vomeronasa 
major palatine a 2. dorsal rasa 
v (By Hillmann) 



41 -PORCINE RESPIRATORS SYSTEM 


1285 


cha, is another low fold of mucous membrane, 
the \entral fold, or basal fold, which contains 
a venous plexus 

The ethmoturbinate bones occupy the fun- 
dic region of the cavity The largest is called 
the middle nasal concha It lies ventral to the 
dorsal nasal concha and extends rostrad as far 
as the caudal end of the \entral nasal concha. 

The projection of the nasal conchae into the 
nasal cavity divides the cavity into passages, 
or meatuses The dorsal nasal meatus lies be 
tween the roof of the cavity and the dorsal 
nasal concha It extends caudad as far as the 
junction of the inner plate of the frontal bone 
with the ethmoid bone 
The middle nasal meatus lies between the 
dorsal and ventral nasal concha and is slightly 
narrower than the dorsal meatus It commu 
nicates with the dorsal recess in the ventral 
concha. The nasomaxillary opening is situated 
in the caudal part of the middle meatus (at the 
level of the fifth or sixth cheek tooth) and is 
covered by the dorsal nasal concha At the 
same level, the middle nasal meatus by means 
of two small openings, also communicates 
with the sinus of the dorsal nasal concha and 
the caudal part of the frontal sinus 
The v entral nasal meatus is larger than ei 
ther the dorsal or middle nasal meatuses It 
is situated between the ventral nasal concha 
and the floor of the nasal cavity, and commu 
nicates with the ventral recess and sinus of 
the ventral nasal concha Caudally it leads 
directly into the nasopharyngeal meatus The 
nasolacrimal orifice, which is the opening of 
the nasolacrimal duct, is situated in the caudal 
part of the ventral meatus 
The nasopharyngeal meatus extends from 
the rostral border of the horizontal plate to 
the choana 

The ethmoidal meatuses are the narrow pas 
sages between the ethmoturbinate bones 
They contain the openings of the parts of the 
frontal lacrimal and sphenoidal sinuses and 
ethmoidal cells 

The common nasal meatus lies between the 
nasal conchae and the septum and extends 
from the roof to the floor of the cavity It con 
nects laterally with the dorsal middle ventral 
and ethmoidal meatuses 
The mucous membrane lining the nasal 
cavity is extremely vascular and bears three 
different types of epithelium In the rostral 
part of the cavity, or vesUbule the mucous 
membrane which may be pigmented is cov 
ered by stratified squamous epithelium and 
contains numerous serous glands The epi 
thelium of the mucous membrane that covers 
the ethmoturbinate bones the caudal part of 
the dorsal nasal concha and its extension into 
the frontal sinus and the adjacent part of the 
nasal septum is olfactory in type The area so 
covered is known as the olfactory region, its 


mucous membrane is brownish in color and 
contains tubular, serous secietmg* olfactory' 
glands The rest of the nasal cavity is known 
as the respiratory region It is covered by a 
reddish mucous membrane that bears a pseu 
dostratified columnar ciliated epithelium 
with numerous goblet cells Within the mu 
cous membrane of the respiratory region are 
numerous tubuloacinar (tubuloah eolar) 
glands Most of these glands are serous se- 
creting but some are mixed serous and mu 
cous 

The serous secreting lateral nasal glnnd is 
located m the mucous membrane and around 
the ostium of the maxillary sinus Its duct 
opens near the nostril at the end of the straight 
fold (Bojsen Moller, 1967) 

The incisive (^nasopalatine) duct is a bilat- 
eral, mucous membranous tube which opens 
into the oral cavity on the lateral aspect of the 
incisive papilla and into the floor of each nasal 
cavity 

The v omeronasal organ consists of two blind 
tubes which are lined by mucous membrane 
and cov ered externally by a thin plate of car- 
tilage (Tigs 41-1 and 2) They lie on either 
side of the ventral border of the nasal septum 
and extend caudad as far as the level of the 
second to fourth cheek teeth Each tube opens 
into the oral cavity in common with the ipsi 
lateral incisive duct The mucous membrane 
on the lateral aspect of the tube bears pseudo 
stratified columnar ciliated epithelium and 
that on the medial wall of the tube olfactory 
epithelium 

The paranasal sinuses are described in the 
Osteology chapter 

Vfssfls and nerves Blood is earned to 
the nasal cavity by the following arteries 
sphenopalatine, ethmoidal, and greater pala 
tine, and by the artenes that supply the snout 
The blood is earned aw ay by the corresponding 
veins The lymphatic vessels drain into the 
mandibular and medial retropharyngeal 
lymph nodes The nerves come from the ol 
factory and branches of the trigeminal 

LARYNX 

The larynx of the pig is relatively long and 
extends from the level of a transverse plane 
through the base of the occipital bone to the 
level of a transverse plane through the fourth 
or fifth cervical vertebra Rostrally the larynx 
is fairly superficial but caudally it is more 
deeply situated 

The larynx is related ventrally to the stemo- 
hyoideus muscle and the ventral part of the 
sternothyroideus muscle laterally to the 
dorsal part of the sternothyroideus, stemo 
cephalicus and omohyoideus muscles the 
linguofacial vein and the mandibular gland 



1286 


PORCINE 



FIGURE 41-2. Transverse section 
of nasal cavity of mature pig (sche- 
matic); caudal view, enlarged. 

A. Incisive bone; C, vomer; D, hard pal- 
ate (mucosa), a, nasal septum (carti- 
laginous), d, vomeronasal organ; d\ 
lumen of d, e, vomeronasal cartilage (be- 
tween the paired vomeronasal organs); f, 
venous plexus and arteries (related to 
major palatine vessels), 1, major palatine 
a. (right); 3, nasal mucous membrane. 
(By Hdlmann) 


and dorsally to the pharynx and the first part 
of the esophagus. 

CARTIIAGE5 OF THE IARYNX 

Cricoid cartilace. The single, ring- 
shaped cricoid cartilage (Fig. 41-3), which is 
situated just rostral to the proximal ring of the 
trachea, is thick and laterally compressed. Its 
oval opening is placed obliquely to the long 
axis of the larynx. The lamina of the cricoid 
cartilage is long and narrow. Its dorsal sur- 
face presents a median muscular ridge which 
is sharp and prominent rostrally but flattened 
cau dally. On cither side the rostral border of 
the lamina presents a convex facet for articu- 
lation with the Ipsilateral arytenoid cartilage. 
On each side of the dorsal surface of the lami- 


na and near the caudal border, there is a con- 
cave facet for articulation with the thyroid car- 
tilage. The ventral surface of the lamina is 
smooth and concave. The arch of the cricoid 
cartilage is narrow and slopes caudoventrally 
so that it lies obliquely to the long axis of the 
larynx. The rostral border of the arch is S- 
shaped. The caudal border is straighter. but 
ventrally it is extended to form a caudally 
projecting point. 

Thyroid cartilace. The unpaired, gutter- 
shaped, thyroid cartilage is very long (Fig. 41- 
4). It has a ventral body and lateral laminae. 
Each lamina is a broad, irregularly shaped, 
quadrilateral plate, which is higher caudally 
than it is rostrally. The caudodorsal angle is 
prolonged to form the short, broad caudal 
cornu, which overlies and articulates with the 




41 -PORCINE RESPIRATORY SYSTEM 


1287 



cricoid cartilage The rostral cornu is absent 
On the lateral surface of the lamina a low 
ridge, the oblique line, extends rostrad for a 
short distance from the dorsal limit of the 
caudal border The body of the thyroid carti 
lage is long and thickened ventrally to form 
the laryngeal prominence The rostral border 
of the body is convex while the caudal border 
presents a median conical projection The 
body of the thyroid cartilage lies rostral to the 
arch of the cncoid cartilage and underlies a 
large part of the floor of the larynx The lami 
nae flank the arytenoid cartilages and form the 
skeleton of a large part of the lateral laryngeal 
wall 

Arytenoid cartilages The paired 
arytenoid cartilages (Fig 41-5) lie rostral to 
the lamina of the cncoid cartilage and are 
flanked by the dorsal parts of the laminae of 
the thyroid cartilage They are irregular in 
shape, but each somewhat resembles a three 
sided pyramid with the apex situated rostrally 
and the base caudally The concave dorsal 
surface is separated from the lateral surface 
by a prominent crest The caudal part of the 
crest forms the muscular process The medial 
surface of the cartilage is flat and the ventral 
border is concave The thick angle formed be 
tween the ventral border and the base is 
known as the vocal process The angle formed 
between the dorsomedial border and the base 
is extended to form a distinct medial projec 
tion When the arytenoid cartilages of either 
side are in situ, the medial projections lie in 
close proximity to each other, with a small ac 
cessory cartilage the interarytenoid cartilage 


between Medially the caudodorsal part of the 
base presents a small concave facet for articu- 
lation with the cncoid cartilage The apex of 
the arytenoid cartilage has fused to it a dor- 
sally projecting comiculate cartilage 
Corniculate cartilages The paired 
cormculate cartilages are fused with the 
apices of the arytenoid cartilages and project 
dorsomesiad The comiculate cartilages are 
quite characteristic in the pig, since they pre 
sent two distinctive parts namely, a dorsal 
part which is conical in form and corresponds 
with the entire comiculate cartilage in other 
species and a lateral part which is crescent 
shaped The apex of the dorsal part is fused 
with its counterpart on the opposite side 
Epiglottic cartilage The unpaired, 
epiglottic cartilage (Fig 41-6) is situated 
rostrodorsad to the rostral border of the bod> 
of the thyroid cartilage It is shaped like an 
orbiculate leaf with its borders upturned The 
lingual surface is concave lengthwise and con 
vex from side to side The larj ngeal surface is 
convex in its length and concave from side to 
side The base is broad and is bent rostrally so 
that it projects toward the basihyoid bone and 
presents a median projection, the petiolus or 
stalk 


ARTICULATIONS, LIGAMENTS 
AND MEMBRANES OF THE 
LARYNX 

The cricothyroid articulation is a synovial 
joint formed between the facet on the caudal 


FIGURE 41-5 Arytenoid cartilage 
with comiculate cartilage, of pig 
Medial aspect (left) lateral aspect (right) 



-lorn cuiare cartilage 
Muscular process, 
Irtco d articular 
surface 
, Vocal process- 




12RS 


PORCINF 



FIGURE 41-6 Epiglottic carti- 
lage of pig 

Dorsal aspect (left) lateral aspect 
right) 


cornu of the thyroid cartilage and the thyroid 
articular surface of the cricoid cartilage The 
main movement is a rotation of the thyroid 
cartilage around the horizontal axis of the 
joint 

The cricoarytenoid articulation is a synovial 
joint formed between the articular surface of 
the arytenoid cartilage and the arytenoid ar 
ticular surface of the cricoid cartilage The 
main movements are a dorsovcntral hinge 
and concomitant gliding of the arytenoid car 
tilage on the cncoid cartilage and a rotation of 
the ar> tenoid cartilage around a perpendicular 
axis through the joint 

The £ancoroiculate articulation is a cart! 
heinous joint formed between the apex of the 
arytenoid cartilage and the cormculatc car 
tihgi 

The Omohyoid articulation is represented 
by the thv rohyetd sy ndesmosis. 

nit cricotrachial ligament is the elastic 
ligament liiat conmcts the caudal border of 
the cricoid cartilage with the cranial border of 
the fast tracheal ring 

Th f cricothyroid ligamrnt is an clastic liga 
moot which connects the rostral border of the 
arch of the cricoid cartilage with the caudal 
borders of the Laminae and the bod) of the 
thyroid cartilage Ventrally there is a large gap 
between the cartilages and in this area, the 
cricothyroid ligament is called the •^cricothy- 
roid membrane The cricothyroid ligament ex 
tends rovtralh along the dorsal surface of the 
body of the thyroid cartilage and terminates 
near its rostral bonier Elastic fibers which 
are detached from the Inner aspect of the cri 
cothyroid ligament and extend into the laryn 
goal mucous membrane are extremely short. 

The cnroarvlenoid ligament is *1 weak fi 
brous band which extends across the ventro- 
medial surface of the cricoarytenoid joint It 
Js attached to the medial surface of the cri 
coid cartilage close to the nrvtenoid articular 
surface and to the medial surface of the ar> 
tenoid cartilage just ventral to the articular 
surface 

The tran«vrr*e arytenoid ligament is a fi 
brous band extending between the dorsomedi 
al angles of the arytenoid cartiLage* A small 


piece of cartilage the interarytenoid cartilage, 
is found embedded in the ligament 
The thyroepiglottic ligament is a thin, 
wide band of elastic fibers that loosely at 
taches the rostral border of the body and the 
ventral parts of the laminae of the thyroid car- 
tilage to the base of the epiglottic cartilage 
The hyoepiglottic ligament consists of two 
parts The middle part is short, thick, and in 
elastic and connects the basal part of the 
rostral surface of the epiglottic cartilage with 
the basihyoid bone The lateral parts are 
elastic and connect the ventral parts of the 
borders of the epiglottic cartilage with the 
thyrohyoid bone 

The thyrohyoid membrane is an elastic 
membrane which extends between the rostral 
border of the lamina and body of the thyroid 
cartilage to the basihyoid and thyrohyoid 
bones Since the rostral cornua of the thyroid 
cartilage are not developed, there are no nr 
ticulations between the thyrohyoid bone and 
the laminae of the thyroid cartilage Instead, 
these parts are held together by connective 
tissue forming the thyrohyoid syndesmosis 

The vocal ligaments are paired elastic liga 
ments On each side a ligament extends from 
the vocal process of the arytenoid cartilage to 
the caudal border of the body of the thyroid 
cartilage where it radiates out into the crico- 
thyroid ligament The fibers of the vocal liga 
ment pass in a vcntrocaudal direction and are 
split longitudinally into rostral and caudal 
bands 

The vestibular (ventricular) ligaments are 
short, paired fibrous bands On each side a 
ligament extends from the basal part of the 
tttudal surface of the epiglottic cartilage to the 
lateral surface of the comjculate or the ary- 
tenoid cartilage 

On each side in the area between the ves- 
tibular and vocal ligaments there is a brood 
band of fibers that fans out from the ventral 
border of the arytenoid cartilage to the inner 
aspect of the lamina of the thyroid cartilage 
MUSCLES OE THE LARYNX 

The extrinsic muscles consist of the th>r»- 
hyoideus, hyoepiglotticus and sternothyroid- 



41 -PORCINE RESPIRATORY SYSTEM 1289 

eus, which are described in detail in the esophageal vestibule On each side, a small 
Myology chapter pocket is formed between the lateral fold and 

The intrinsic muscles consist of the follow- the mucous membrane covering the comicu- 
mg and are also described in detail in the late and arytenoid cartilages 
Myology chapter the cncothyroideus, crico- The mucous membrane covenng the vocal 
arytenoidei dorsalis and lateralis, arytenoid- ligament evaginates on each side through the 

eus transversus, and thyroarytenoideus. How- space between the two parts of the ligament 

ever, a bnef description of their action is as It then expands rostrally, to he between the 

follows The cncothyroidei muscles tense the connective tissue fibers of the fan shaped 

vocal ligaments (and folds) by approximating band extending between the ventral border of 

the ventral part of the arch of the cncoid the arytenoid cartilage and the lamina of the 

cartilage and the body of the thyroid cartilage, thyroid cartilage and the thyroarytenoideus 

thereby increasing the dorsoventral diameter muscle The depression formed between the 

of the glottis This action also has the effect two parts of the vocal ligament is known as the 

of adducting the vocal folds The thyroary- lateral ventricle (Fig 41-7), and the rostral 

tenoideus, arytenoideus transversus and extension of the mucous membrane is known 

cricoarytenoideus lateralis muscles adduct as the larjngeal saccule * The mucous mem- 

the vocal processes of the arytenoid cartilages, brane covenng the ‘caudal part of the vocal 

thereby slackening and adducting the vocal ligament and the underlying part of the thy- 

folds and narrowing the nma glottidis The roary tenoideus muscle forms the vocal fold 

cncoarytenoideus dorsalis and arytenoideus In the floor of the larynx the mucous mem- 
transversus muscles abduct the vocal proc brane is evaginated between the base of the 

esses and, at the same time, move them epiglottic cartilage and the rostral border of 

dorsad so that the rtma glottidis is widened the body of the thyroid cartilage This median 

and the vocal ligaments (folds) are tensed depression is known as the middle ventricle 

Newts supply of the intrinsic muscles (Fig 41-7) 

AH the intrinsic muscles of the larynx are sup- The mucous membrane from the aditus to 

plied by the recurrent laryngeal nerves, ex the rima glottidis, including the evagmation 

cept the cncothyroidei muscles, which are of mucous membrane or the lateral ventricle, 

supplied by the cranial laryngeal nerves bears stratified squamous epithelium Caudal 

Mucous membrane of the larynx The to this level the mucous membrane bears 

mucous membrane of the larynx is continuous pseudostratified columnar ciliated epithelium, 

with that of the. laryngopharynx rostrally and Taste buds are present in the epithelium on 

that of the trachea caudally It is firmly at the caudal aspect of the epiglottis The lamina 

tached over the caudal aspect of the epiglot- propna contains many elastic fibers as well 

tis, the vocal ligaments, and the inner surface as serous, mucous, and mixed glands Solitary 

of the cncoid cartilage, but elsewhere it is lymph follicles are found in the mucous mem 
loosely attached brane of the epiglottis, in the small pocket be- 

A lateral fold of mucous membrane is de- tween the lateral fold and the cormculate and 
tached from the apical part of the border of arytenoid cartilages, in the lateral ventncle, 

the epiglottic cartilage on either side The and at the base of the epiglottis The latter 

lateral folds (Prodinger, 1940) extend dorso group of lymph follicles compnse what is 
caudad and blend with each other over the called the paraepiglottic tonsil 

dorsal aspects of the arytenoid and cricoid 

cartilages to form part of the floor of the *See footnote page 124 


FIGURE 41-7 Medial view 
of lar'ynx of pig 




CAVITY OF THE LARYNX 


The cavity of the larynx connects the cavity 
of the laryngopharynx with that of the trachea. 
The entrance into the cavity is set oblique.y 
and faces rostrodorsally It is bound rostrally 
by the epiglottis laterally by the lateral folds 
and caudodorsally by the comiculate cam 
lages The part of the cavity between the en 
trance and the vocal folds is known as the 
vestibule The part of the cavity bounded by the 
vocal folds, the vocal processes, and the ad 
jacent parts of the medial surfaces of the ary 
tenoid cartilages is called the nma glottidis 
The caudal compartment of the larynx ex 
tends from the rima glottidis to the outlet of 
the larynx, which is bounded by the caudal 
border of the cricoid cartilage The vestibule 
is quite wide, but the caudal compartment is 
narrow because the cncoid cartilage is lateral 
ly compressed 

Vessels and nerves The artery supplying 
the larynx is the cranial laryngeal artery, 
which anses from the common carotid artery 
near its termination The veins drain into the 
internal jugular vein The lymphatic vessels 
drain into the medial and lateral retropharyn 
geal lymph nodes and the deep cervical lymph 
nodes 


PORCINE 

principal bronchi, dorsal to the base of the 
heart The trachea is more or less median in 
nty position except for its terminal part, which is 
iea pushed to the right by the aortic arch On the 
lely right side, at the level of the third intercostal 
ally space, the trachea gives off a bronchus to the 

Ids apical lobe of the right lung. 

irti The part of the trachea that lies in the neck 
en is called the cervical part, and the part that 
the Ues in the thoracic cavity is called the thoracic 


The cervical part of the trachea is related 
dorsally to the longus colli muscles, except for 
the cranial few centimeters where the esopha 
gus intervenes, ventrally to the caudal deep 
cervical lymph nodes and the sternothyrohy* 
oidei muscles, and laterally to the stemoce- 
phalicus, brachiocephalicus, and scalenus 
muscles On the left side in the caudal 
part of the neck, the trachea is related dorso 
laterally to the esophagus On either side 
the common carotid artery, the internal 
jugular vein, the vagosympathetic trunk, 
and the recurrent laryngeal nerve, all en 
closed in the carotid sheath, cross the lateral 
surface of the trachea obliquely, starting from 
a dorsolateral position at the cranial end and 
ending in a ventrolateral position at the en 
trance to the thoracic cavity Just ventral to 


The sensory nen e supply is as follows the 
nerves of the mucous membrane of the larynx, 
as far caudal as the vocal fold, are the internal 
branches of the cranial laryngeal nerves, 
which are branches of the vagus nerves The 
internal laryngeal nerve reaches the interior 
of the larynx by passing through the dorsal 
part of the thyrohyoid membrane between the 
lamina of the thyroid cartilage and the thy 
rohyoid bone The mucous membrane of the 
larynx caudal to the vocal folds is innervated 
by branch es of the recurrent laryngeal nerv es 
The branches enter the larynx by passing 
through the dorsal part of the cricothyroid 
membrane, between the lateral part of the 
arch of the cncoid cartilage and the lamina of 
the thyroid cartilage 

The motor nerve supply is as follows The 
cricothyroideus muscle is supplied by the 
external branch of the cranial laryngeal nerve. 
All the other intrinsic muscles are supplied 
by branches of the recurrent laryngeal nerve 


TRACHEA 

The trachea is a flexible, cartilaginous and 
membranous tube that forms the proximal 
part of the tracheobronchial tree. It is about 
15 to 20 cm long and extends from the larynx, 
at the lev el of the fourth or fifth cervical ver 
tebra to the lev el of the fifth thoracic vertebra, 
where it bifurcates Into the right and left 


the carotid sheath, the external jugular veins 
are related to the lateral aspects of the tra 
chea. Just caudal to the larynx, the lateral and 
ventral walls of the trachea are related to the 
lobes and isthmus of the thyroid gland. The 
thyroid gland usually extends from the level 
of the larynx to the level of the sixth or eighth 
cartilaginous plate, but sometimes it lies fur- 
ther caudad. In the young animal, up to one 
year of age, the thymus gland is present in the 
neck and is related to the ventral aspect of the 
trachea. 

The thoracic part of the trachea lies in the 
cramodorsal part of the mediastinum It is 
related ventrally to the brachiocephalic veins, 
the cranial vena cava, the brachiocephalic 
trunk, the left and right common carotid ar- 
teries, the cranial mediastinal lymph nodes, 
the left recurrent laryngeal nerve, and the 
nght cardiosym pathetic nerves Dorsally the 
trachea is related to the longus colli muscles 
The trachea is related on the left to the left 
vagus and cardiosympathetic nerves and, 
near its bifurcation, to the aortic arch and the 
left tracheobronchial lymph node. In the 
young animal it is also related to the thymus 
on the left The esophagus lies on the left 
dorsolateral aspect of the trachea, close to the 
bifurcation it moves dorsomedially to he on 
the dorsal aspect The trachea Is related on the 
right to the common arterial trunk and satel 
me vein for the costocervical, deep cervical 
and vertebral vessels, the ansa subclavia, the 
right vagus and cardiosympathede nerves, the 



1291 


41— PORCINE RESPIRATORY SYSTEM 


Tracheal mu»c!e 



FIGURE 41-8. Cross section of tracheal ring of 
pig- 

right azygos vein/ the right and cranial tra- 
cheobronchial lymph nodes and the apical 
lobe of the right lung. 

The wall of the trachea consists of four 
layers: a mucosa, a submucosa, a musculocar- 
tilaginous layer, and an adventitia. The struc- 
ture of ,the mucosa, the submucosa, and the 
adventitia is as described in the general sec- 
tion of the respiratory system and so the pres- 
ent account will be restricted to describing 
the species characteristics of the musculocar- 
tilaginous layer. 


•The right azygos vein is reduced in length and usually 
only receives the right second to fourth or fifth intercostal 
veins, because the main dorsal drainage from the intercos- 
tal veins is by the left azygos vein. 


There are between 32 and 36 cartilaginous 
plates in the trachea. These are bent so that 
on transverse section the outline of the tra- 
chea is more or less cylindrical, although it 
may be slightly flattened dorsally in the cervi- 
cal region. The free ends of the plates overlap 
a little, dorsally, with the right side overlying 
the left (Fig. 41-8). In the dorsal part of the 
tracheal wall, the tracheal muscle lies trans- 
versely and is attached to the inner surface of 
the cartilaginous plates. 

The lumen of the trachea is smaller than 
that of the larynx and is subject to some 
change in size under the action of the trache- 
al muscle (Negus, 1965). 

Vessels and nerves. The arteries supply- 
ing the tracheal wall are: branches from the 
common carotid arteries and, in the region of 
the bifurcation, branches of the broncho- 
esophageal arteries. The blood is drained by 
tributaries of the internal and external jugu- 
lar veins, and the broncho-esophageal veins. 
The lymphatic vessels drain into the deep cer- 
vical, cranial mediastinal and tracheobron- 
chial lymph nodes. The nerves supplying the 
trachea are; parasympathetic and sensory 
nerve fibers from the recurrent laryngeal 
nerves, and sympathetic nerve fibers from the 
middle cervical ganglion and from the sym- 
pathetic trunk. 


THORACIC CAVITY 


The thoracic inlet is oval in outline. Its 
height is about 10 cm and its greatest width 
about 5 cm. The lateral walls of the cavity are 
not as flat as they are in the horse or ruminant, 
and, therefore, the cross-sectional outline of 
the cavity at the level of the sixth or seventh 
rib is more cylindrical. The cavity increases in 
width fairly evenly from the first to the elev- 
enth rib, where it is about 25 to 28 cm wide. At 
the level of the last stemebra, the sagittal 
diameter is about 20 cm. The dorsal wall of 
the cavity is over twice as long as the ventral 
wall, since there are 14 or 15 thoracic verte- 
brae and only six stemebrae. The thoracic 
outlet, marked by the costal attachments of 
the diaphragm, is oblique. The diaphragm 
is attached from the xiphoid process of the 
sternum along the costal cartilages of the 
eighth, ninth and tenth ribs to the costo- 
chondral junctions of the tenth ribs. From 
there, it extends in a more or less straight 
Ime to the fourteenth ribs at the junction 
of their middle and ventral thirds. In the 
median plane, the diaphragm slopes cranio- 
ventrad quite steeply from the body of the 
eleventh or twelfth thoracic vertebra to the 
i cos tochondral Junctions of the 

sixth ribs, and then to the sternum. 


THE PLEURA AND 
ENDOTHORACIC FASCIA 


The endothoracic fascia and the pleura are 
well developed. The two pleural sacs are com- 
plete and do not communicate through the 
caudal mediastinum. The right pleural sac is 
considerably larger than the left because of 
the difference in the size of the lungs. The 
cupulae pleurae do not extend cranially to 
the first pair of ribs. On either side, the dia- 
phragmatic line of pleural reflection extends 
along the seventh and eighth costal cartilages 
to the costochondral junction of the eighth 
rib. From there it extends in a gentle curve, 
with a ventral convexity, to the middle of the 
fourteenth rib and thence caudad toward the 
median plane (the presence of a fifteenth rib 
does not affect the diaphragmatic line of pleu- 
ral reflection). A serous sac extends cranially 
from the esophageal hiatus for a distance of 
7.5 to 10 cm. It lies ventral to the aorta and to 
the right of the esophagus. 

The dorsal parts of the crania! and caudal 
mediastinum and the entire middle mediasti- 
num lie mainly in the median plane. However, 
the ventral part of the cranial mediastinum is’ 



r pBCIVE 


pushed to the left by the apical lobe of the 
right lung so that the mediastinal pleura is 
contact with the left costal pleura and the 
part of the caudal mediastinum ventral to the 
esophagus is pushed tu the left by the acces 
sory lobe of the nght lung 


LUNGS 

The lungs are the paired organs nght and 
left (Fig. 41 9) that occupy most of the space 
in the thoracic cavity Each lung is covered 
by pulmonary pleura and mvaginated in the 
ipsilateral pleural sac in which it is free to 
move since it Is anchored only by its root and 
the pulmonary ligament. 

The nght lung is subdivided by interlobar 
fissures into four lobes* --^apical (cranial) 
middle (cardiac) ^diaphragmatic (caudal) 
and accessory (intermediate) (Fig 41-10) it 
is a little larger than the left lung which has 


only two lobes*— ^apical (cranial) and <£dia 
phragmatic (caudal) t 

Each lung presents for purposes of descrip- 
tion a cranial apex a caudal base (diaphrag 
matic surface) two surfaces (costal and medi 
al) and three borders (dorsal ventral and 
basal) 

The base of the lung or diaphragmatic sur 
face is related to the convex thoracic surface 
of the diaphragm. It is concave (more or less 
oval m outline) and completely bounded by 
the basal border except in the nght lung 


"See footnote page 135 

1 This i* contrary to the descriptions of Barone (1959) 
and Talantl (1959) who describe the left lung as having 
three lobes corresponding to an apical, a middle and a 
diaphragmatic but consistent with the rationale on lobes 
and bronchopulmonary segments put forward in the 
Ceneral Section. 


TrocAr* Etophapu 



^ ).ungs anft 'heart oT pig ventral new 


L.1 Ac 5f ,w * >r k* 1 * rfsht lung F.d diaphragmatic surface of lungs i left brachial anerv 1 Kr,.-*.! . . 

3 apex of heart 4 pericardium (cut edge) 5 phca venae cava* 6 caudal vena cava 7 ? Vnk , 

nerre trunk 9 aorta. esopnagut 8 ventral esophageal 



Trachea 


41 -PORCINE RESPIRATORY SYSTEM 
Dorsal border 


1293 



Middle lobe Accessory lobe 
FIGURE 41-10. Right lung of pig; medial view. 


j, Left bronchus (cut off), 2, pulmonary arteries, 3, pulmonary veins, 4, caudal vena cava; 5, groove for cranial vena 
cava, 6, groove for vena azygos, 7, groove for aorta, 8 (placed on groove for esophagus), lines of pleural reflection Arrows 
indicate Interlobar fissures 


where the accessory lobe is also related to the 
diaphragm. 

The apex of the lung occupies the space 
formed by the cupula pleurae. The apex of 
the right lung is larger than that of the left 
lung. 

The costal surface, the largest surface, is 
smooth and convex in conformity with the 
inner surface of the lateral thoracic wall, and 
may bear costal impressions in lungs that 
have been hardened in situ. 

The medial surface is less extensive than 
the costal surface. Cranially the mediastinal 
part has a well-marked concave area which is 
related to the heart in its pericardium and is 
known as the cardiac impression. Dorsal to the 
cardiac impression is an area of the lung not 
covered by pleura which contains the bronchi, 
blood and lymphatic vessels, and nerves en- 
tering and leaving the lung. The areais known 
as the hilus of the lung, and the structures 
entering and leaving form the root of the lung. 
Caudal to the hilus is a small triangular area, 
not covered by pleura which is bounded dor- 
sally and ventrally by the layers of the pul- 
monary ligament When the lungs are in situ 
these uncovered areas maybe in contact. 

The relative positions of the structures en- 
tering or leaving at the hilus are as follows; In 
the right lung the principal bronchus is lo- 
cated in the caudodorsal part of the hilus with 
the small bronchial artery and the dorsal part 
of the pulmonary plexus on its dorsal surface, 
and with the bronchial veins and lymphatic 
vessels around it The pulmonary vein that 
drains the diaphragmatic and accessory lobes 
is caudal to the bronchus. The nght pulmonary 
artery with the associated ventral part of the 


pulmonary plexus is ventral or cranioventral 
to the bronchus, while the vein that drains the 
middle lobe is ventral to it The right apical 
lobar bronchus is situated in the cranial part 
of the hilus with the apical lobar artery and 
vein ventral to it. 

In the left lung the principal bronchus is 
located in the dorsal part of the hilus, with the 
bronchial artery and the dorsal part of the pul- 
monary plexus on its dorsal aspect and with 
the ventral part of the pulmonary plexus on 
its ventral aspect. The pulmonary artery is 
situated cranial to the principal bronchus. The 
vein that drains the apical lobe is ventral to 
the bronchus, and the vein that drains the di- 
aphragmatic lobe is caudoventral to the bron- 
chus. 

In lungs that have been hardened in situ the 
mediastinal parts of the medial surfaces bear 
a number of impressions made by various 
mediastinal structures that are in contact 
with the lungs. In the right lung there is a 
horizontal groove formed by the trachea ex- 
tending cranially from the principal bronchus 
to the apex of the lung. Ventral to this groove, 
and cranial to the cardiac impression, is a 
horizontal groove formed by the cranial vena 
cava Cranially there is a small vertical groove 
for the costocervical vein. Extending caudad 
from the dorsal part of the hilus, there is a 
shallow horizontal groove formed by the 
esophagus 

In the left lung, just cranial to the hilus, 
there is a narrow, curved, vertical groove 
formed by the left azygos vein. Two shallow 
horizontal grooves extend caudad from the 
dorsal part of the hilus— the dorsal one 
formed by the aorta and the ventral one by the 



1294 ruww 

esophagus In addition, there maybe a shallow 
groove formed by the left subclavian artery 
dorsal and cranial to the cardiac impression. 

The ventral border of each lung is sharp 
and irregular It is indented at the level of the 
heart to form the cardiac notch. The cardiac 
notch is narrow and deep in the right lung and, 
when the organs are in situ, it permits the 
heart in its pericardium to come into relation 
with the right lateral thoracic wall in the re- 
gion of the ventral end of the third rib and the 
adjacent intercostal spaces In the left lung 
the cardiac notch is wide and shallow and, 
when the organs are in situ, the heart in its 
pericardium is related to the left lateral tho- 
racic wall in an area bounded cranially by the 
apical lobe of the right lung and dorsally and 
caudally by the ventral border of the left 
lung. This area is in the ventral one-third of 
the second and third intercostal spaces and in 
the ventral part of the fourth intercostal 
space 

The dorsal border of each lung is thick and 
rounded. It forms the dorsal boundary be- 
tween the costal surface and the vertebral 
part of the medial surface 
The basal border of each lung separates the 
diaphragmatic surface from the medial and 
costal surfaces The border is smooth and 
rounded between the diaphragmatic and me- 
dial surfaces, and thin and sharp between the 
diaphragmatic and costal surfaces. The latter 
part extends toward, but does not fully oc- 
cupy the costodiaphragmatic pleural recess, 
except perhaps during deepest inspiration. It 
follows a slightly curved line, with a ventral 
convexity, from the costochondral junction 
of the sixth rib to the vertebral end of the 
second from last intercostal space The inter 
lobar fissures subdividing the lungs Into 
lobes vary somewhat in their length and 
depth from one lung to another and, thereby, 
slightly alter the external appearance of the 
lungs 

In the right lung, the tfapieal lobe com 
prises a fairly large part of the lung. When the 
lungs are in situ, the apical lobe extends to the 
left of the median plane cranial to the heart 
and its pericardium, and ventral to the great 
vessels in the cranial mediastinum. In the 
young animal the presence of the thymus in 
the cranial mediastinum limits the expansion 
of the right apical lobe The medial surface of 
the apical lobe contains the cranial half of the 
cardiac impression. The caudal boundary of 
the lobe may be marked to a variable extent 
and depth by a fissure Ventrally the- caudal 
boundary follows a line running caudodorsaily 
from the depth of the cardiac notch to the 
junction of the dorsal and middle thirds of the 
lung at the level of the tracheal bifurcation, 
and separates the apical lobe from the middle 
lobe From there the caudal boundary follows 
a transverse line and separates the apical 


lobe from the diaphragmatic lobe The apical 
lobe can be divided into cranial and caudal 
parts, or bronchopulmonary segments The 
plane of division is indicated roughly by a 
transverse plane through the deepest part of 
the cardiac notch 

The middle lobe Is shaped like a pyramid, 
with its base forming the costal surface of the 
lobe and its apex directed toward the hllus of 
the lung. It is related cranially to the apical 
lobe and caudally to the diaphragmatic lobe, 
from which it is separated by a deep fissure, 
this fissure may connect dorsally with the fis- 
sure separating the apical and middle lobes 
The craniomedial surface of the middle lobe 
forms the caudal half of the cardiac impres- 
sion. 

The ^diaphragmatic lobe, the largest lobe, 
is caudal in position It is related cranially to 
the apical and middle lobes and has attached 
to its medial surface, just caudal to the hllus, 
the accessory lobe 

The accessory lobe Is pyramidal in shape, 
with its slightly concave base related to the 
diaphragm and its apex directed toward the 
hilus of fhe lung. Ventrally, the accessory and 
diaphragmatic lobes are separated by a fissure 
that opens in its dorsal part to form a canal for 
the caudal vena cava and the right phrenic 
nerve The plica venae cavae lies in the fis- 
sure between these lobes 
In the left lung the <£apical lobe is the cranial 
and smaller lobe It is separated from the 
larger ^diaphragmatic lobe by a fissure that 
extends Into the lung for a variable distance 
The apical lobe Is L-sbaped and consists of two 
parts or segments a cranial, apical part arid a 
caudoventral, middle part. The division be- 
tween these two parts is indicated roughly by 
a line drawn from the angle of the cardiac 
notch toward the hilus of the lung. The medial 
surface of the apical lobe presents the cardiac 
impression. 

The pulmonary pleura has a relatively thick 
subserous layer which Is continuous with the 
intrapulmonary connective tissue The Inter- 
lobular septae are fairly thick and complete, 
and the boundaries of the lobules are mapped 
out on the surface of the lung. 

THE BRONCHIAL TREE 

The trachea gives off a tracheal, or right 
apical lobar bronchus (Fig 41-11) from its 
right side at about the level of the third rib It 
then bifurcates into right and left principal 
bronchi at a point slightly to the right of the 
midline at the level of the fifth intercostal 
space 

The right apical lobar bronchus is short It 
passes laterad from the trachea to enter the 
right lung In the craniodorsal part of the hilus 
Shortly after it has entered the lung, the right 
apical lobar bronchus divides into cranial and 



41 -PORCINE RESPIRATORY SYSTEM 


1295 



FIGURE 41-11. Teased lungs of pig; dorsal rlew. 


A. Apical lobe: a. apical lobe, cranial segment; a\ apical lobe, caudal segment; B. middle lobe; C. diaphragmatic lobe D. 
accessory lobe, T, trachea; 1, left tracheobronchial lymph node; 2. right tracheobronchial lymph node, 3, middle 
tracheobronchial lymph node; 5. cranial tracheobronchial lymph node. 


caudal segmental bronchi. The cranial bron- 
chus passes cranloventrad to ventilate the 
cranial part, or bronchopulmonary segment, 
of the lobe, while the other bends caudally to 
supply the caudal part, or bronchopulmonary 
tejcment, of the lobe. 

The right principal bronchus passes caudo- 
btterad to enter the right lung In the caudo- 
dorsal part of the hilus. Shortly after the prin- 


cipal bronchus has entered the lung, it gives 
off a bronchus from its ventrolateral aspect, 
the right middle lobar bronchus, which passes 
ventrolaterad to ventilate the middle lobe. The 
right middle lobar bronchus subsequently di- 
vides into ventral and dorsal bronchi which 
ventilate the ventral and dorsal bronchopul- 
monary segments of the middle lobe, respec- 
tively. 



1296 


After giving off the middle lobar bwnchus 
the principal bronchus gives off a bronchus 
from its ventromedial aspect, the accessory 
lobar bronchus which passes caudomesiad to 
ventilate the accessory lobe The accessory 
lobar bronchus divides into two bronchi which 
ventilate the dorsal and ventral bronchopul 
monary segments of the accessory lobe 
The continuation of the principal bronchus 
the nght diaphragmatic lobar bronchus ven 
tilates the diaphragmatic lobe The first two 
bronchi that arise from the ventrolateral as 
pect of the lobar bronchus ventilate the ven 
tral basal and lateral basal bronchopulmonary 
segments respectively, while the first two 
bronchi that arise from the dorsal aspect of 
the lobar bronchus ventilate the cranial dorsal 
and the caudal dorsal bronchopulmonary seg- 
ments respectively After the diaphragmatic 
lobar bronchus has given off these four bron 
chi, it continues as the dorsal basal segmental 
bronchus and ventilates the dorsal basal seg- 
ment One or two bronchi, which ventilate 
small areas on the medial aspect of the lobe, 
may be given off by the lobar bronchus 
The left principal bronchus passes laterad 
and slightly caudad from the tracheal bifurca 
tion to enter the left lung in the dorsal part of 
its hilus Shortly after it enters the lung, the 
pnncipal bronchus gives off a bronchus from 
its lateral aspect This bronchus, the apical 
bronchus ventilates the apical lobe The api 
cal lobar bronchus is short and terminates by 
dividing into two bronchi one, the cranial 
segmental bronchus, runs craniad to ventilate 
the cranial part (bronchopulmonary segment) 
of the lobe, the other, the caudal segmental 
bronchus, runs ventrolaterad to ventilate the 
caudal part (bronchopulmonary segment) of 
the lobe 

After the pnncipal bronchus has given off 
the apical lobar bronchus, it ventilates the 
diaphragmatic lobe and is known as the left 
diaphragmatic lobar bronchus The broncho- 
pulmonary segmental arrangement of the 
diaphragmatic lobe and the ongin of the seg 
mental bronchi from the lobar bronchus are 
similar in the left lung to those of the nght 
lung. 

The terminal part of the bronchial tree usu 
ally consists of terminal bronchioles leading 
directly into alveolar ducts, but some of the 
terminal bronchioles may lead into poorly 
developed respiratory bronchioles 

Vessels and nerves The branches of the 
pulmonary artery carry venous blood to the 
lungs and accompany the bronchi By far the 
greatest part of the blood from the lungs and 
the blood from the pulmonary pleura is re- 
turned to the left atrium of the heart by the 
pulmonary veins (For description, see the 
general chapter on the respiratory system ) 

The lobes are drained exclusively by their 


PORCINE 

lobar veins except for areas that are adjacent 
to other lobes The lobar veins are always 
closely associated with the corresponding 
lobar bronchi and, generally speaking, lie on 
the opposite side of the bronchi to the pul- 
monary arteries In all except the diaphrag- 
matic lobes, the veins closely follow the rami- 
fications of the bronchial tree and, in general, 
he on the opposite side of the airways to the 
pulmonary arteries In the diaphragmatic 
lobes, the smaller veins would appear to lie in 
the connective tissue planes between areas of 
the lung rather than alongside the axial air- 
ways and arteries (Tondury and Picco, 1952) 
TTie unpaired bronchial branch (artery) 
anses from the ventral aspect of the aorta in 
common with the cranial esophageal artery 
forming a .broncho-esophageal artery The 
bronchial branch passes ventrad over the nght 
surface of the esophagus to reach the dorsal 
aspect of the tracheal bifurcation Here it di- 
vides into the left and nght bronchial 
branches, the bronchial branch to the right 
apical lobe, and branches to the trachea. 

The bronchial branches which enter the 
lung on the dorsal aspects of the principal 
bronchi and the right apical lobar bronchus 
give off branches to the tracheobronchial 
lymph nodes and to the pleura In the region of 
the hilus Within the lung the bronchial 
branches are to be found coiling around the 
bronchi and giving off branches to the bron- 
chial wail and vasa vasorum to the pulmonary 
vessels The bronchial branches also give rise 
to branches that pass to the surface of the lung 
in the interlobular septae and supply the pul 
monary pleura. The bronchial branches ter- 
minate at the distal ends of the terminal 
bronchioles in a common capillary bed with 
branches from the pulmonary arteries 
(McLaughhnetaL 1961) 

The bronchial veins are present as described 
in the general section on the lung. The lym 
phatic vessels and the pulmonary lymph nodes 
are arranged as described in the lymphatic 
chapter The nerve supply to the lungs and to 
the pulmonary pleura is as described m the 
neurology and general chapters 


BIBLIOGRAPHY 

? r0 2 Cl J? « pulmonalrea che* It port 

d * 1 A *’° Cla ' lon d " AntMmlttM XLV Mwnlon 

80 <1 development of anterior 
MvJ nU.V -1 in j AnaL jdi 321 33; 

McLaughlin R. F W S Tjrter and R. O Canada. 1901 AMudroflhe 

J08 anJ “ mT ^ A~*- 

Negus V 1965 The Biology of Revplraiion, London. E. and S 
Lhingrton Lid pp 109-110. 

PnxJlnger T 1940 Die Artmerk male de. Kehlkopfe, der Hauv 
•,!»*» gutal Dltaertatlon. Leipzig. 

lh * ,un »* * n ‘he pig Anat. Ant., JOB 68- 
•mlt der Scbwrlnelunge 



CHAPTER 


42 


PORCINE 

UROGENITAL 

SYSTEM 

by S. Sisson 


URINARY ORGANS (ORGANA UROPOETICA) 


KIDNEYS (REN) 

The kidne>s are smooth and bean-shaped 
(Fig 42-1), they are more flattened dorso- 
vcntrally, more elongated and smaller at the 
extremities than those of the dog Their color 
is brown The length is about twice the width 


They are usually almost symmetrically placed 
ventral to the transverse processes of the 
first four lumbar vertebrae, but the left 
kidney is often a little farther craniad than the 
nght one. The lateral border lies against the 
flank parallel with the edge of the longis- 
simus muscle The caudal extremity is 


KIGUIIK 42-1. KidncjB of 
P»JT in situ; ventral » ic* . 

1. Hctmic a . 2. splenic a. 



1297 



1298 


PORCINE 



Frontal section of kidney 
of pig. 


usually about midway between the last rib 
and the coxal tuber. The cranial extremity of 
the right kidney has no contact with the liver. 
There is a well-developed fat capsule associa- 
ted with the kidney. 

Variations in position are not rare and 
involve the left kidney more often than the 
right; the former has been found near the 
pelvic inlet. When a fifteenth rib is present 
the cranial end of the kidney is usually 
vewxal U. The tight kidtwj is, v&uaWf 
separated from the hver by an interval of 
2.5 cm or more. Absence of the left kidney has 
been recorded. 

The weight of the kidney of an adult pig is 
about 200 to 250 gtn. The ratio of their 
combined weight to that of the body is about 
1:150 to 200. The length in an adult of good 
size is about 12.5 cm and the greatest width 
about 6.0 to 6.5 cm. 

Structure. The hilus is approximately 
in the middle of the medial border. The pelvis 
is funnel-shaped and divides Into two major 
calices, which ptass in a curve cranially and 
cau dally, respectively, and give off some 
eight to 12 short minor calices; each of the 
latter contains a papilla (Fig. 42-2). Some 
papillae are narrow and conical and corre- 
spond to a single pyramid; others are wide and 
flattened and result from the fusiort of two 


or more pyramids; some project directly 
through the wall of the renal pelvis without 
the formation of a calyx. The renal pyramids 
are distinct, but it is apparent that some are 
compound, i.e., formed by fusion of primi- 
tively separate pyramids; renal columns are 
present between the pyramids. The loops of 
Henle are long. The renal vessels enter the 
ventral part of the hilus, dividing into 
lobar branches between the pyramids; the 


URETERS 

The only special features in regard to the 
ureter are that it is at first relatively wide and 
gradually diminishes in caliber and that it is 
slightly flexuous, leaving the kidney in a 
sharp caudal curve (Figs. 44-11, 12 and 15). 


‘ URINARY BLADDER 
(VESICA URINARIA) 

The urinary bladder is relatively very large; 
when full, it lies chiefly in the abdominal 
cavity (Figs. 44-11, 12 and 15). The dorsal 
surface is almost completely covered with 
peritoneum, but the serous covering ventrally 
does not extend so far caudad. 



42— PORCINE UROGENITAL SYSTEM 


1299 


MALE GENITAL ORGANS (Fig 42-3) 


SCROTUM 

The scrotum is situated a short distance 
from the anus and is not so sharply defined 
from the surrounding parts as in the other 
animals 


lobulation correspondingly distinct The 
parenchyma is gray and often dark in fat 
animals There is a rete testis from which 
seven or eight efferent ducts proceed to the 
epididymis 


TESTIS 

The testicles are very large and are regularly 
elliptical m contour (Figs 44-11 and 15) 
They are so placed that the long axis is directed 
dorsally and caudally, the free border being 
superficial and the tail of the epididymis 
highest They are comparatively soft in 
texture The tumca albuginea contains much 
elastic tissue but no muscular fibers The 
mediastinum testis is an axial strand of 
fibroelastic tissue from which interlobular 
septa radiate Other septa are given off from 
the deep face of the tunica albuginea The 
interlobular tissue is abundant, and the 



KlGlIItE 42-3 Genital organs of boar 


a.Te*tlde b epldldyml* c ductu* deferens d testlcu 
Ur a e vesicular gland e. excretory duct* of e f body or 
Pro*ute g bulbospontlosus 1 peril* 1 tigtnold flexure 
of Penl* r spiral cranial part of pent* exposed by stilting 
prepuce m orifice of preputial pouch n retractor 
The vesicular glands are drawn laterad to show the 
•micture* which In the rum ml petition arc covered by 
(lium Lllrnberger and Baum 160S ) 


EPIDIDYMIS 

The epididymis is closely attached to the 
testicle, its tail is very large and forms a 
blunt conical projection at the caudal end of 
the testicle (Fig 44-11) 


SPERMATIC CORD 
(FUNICULUS SPERMATICUS) 

The spermatic cord is necessarily very long 
(20 to 25 cm in a boar of medium size) It 
begins at the deep inguinal ring, where its 
constituent parts come together, extends 
obliquely ventrally through the inguinal 
canal, passes over the side of the penis and 
ends at the attached border of the testicle It 
consists of the following structures 

1 The testicular artery 

2 The testicular veins, which form the 

pampiniform plexus around the artery 

3 The lymphatics which accompany the 

veins 

4 The testicular plexus of autonomic 

nerve, which run with the artery 

5 The ductus deferens and artery and vein 

6 Bundles of smooth muscular tissue 

about the vessels (former cremaster 

intemus m ) 

7 The visceral layer of the vaginal tunic* 


DUCTUS DEFERENS 

The ductus deferens in its testicular part is 
flexuous and closely attached by the vaginal 
tunic, it forms no distinct ampulla The 
cremaster muscle is well developed (Fig 
44-11) and extends to about the middle of 
the scrotal part of the tunic 


Accessory Genital Glands 


VESICULAR GLANDS 

The vesicular glands are exceedingly large, 
and extend into the abdominal cavity (Figs 
44-11 and 15) The} are three-sided pyra 


'Occasionally the clinician* rend to Include In addition 
the parietal Uyrr and the structures lying outride It 
namely the (external) crema*ter muscle and vet sett and 
the genitofemoral nerve 



ronciNE 


1300 

midal masses m apposition with each other 
medially, and cover the caudal part of the 
bladder and the ureters the ductus deferens 
the body of the prostate and the cranial part 
of the urethra and bulbourethral glands 
Tliey are pale pink in color distinctly lobate 
and glandular in structure and enclosed in a 
thin fibrous capsule Half a dozen or more 
large, thin walled ducts emerge from the 
medial surface of each and converge to a 
much smaller excretory duct The latter 
passes caudally lateral to the ductus deferens 
and terminates at a slit like opening on the 
seminal colliculus The two ducts may unite 

In the adult boar the vesicular glands are about 1? to 1 5 
cm long 5 to 8 cm wide and 4 to 5 cm thick they weigh 
about 170 to 225 gm each They have a branched tubular 
structure and are distinctly divided Into lobules Many of 
the tubules are extremely wide (as much as 2 mm In di 
ametet) and are beset with bay like extensions and short 
wide branches These axial spaces of the lobules are 
succeeded by the efferent ducts The cavities are lined by 
a single layer of columnar cells The secretion Is thick and 
turbid and has an acid reaction- 


PROSTATE 

The prostate consists of two parts, as in the 
ox. The body is about 2 5 cm wide and over 
lies the neck of the bladder and the urethra 
at their junction It is concealed by the vesic 
ular glands (Fig 44-15) The pars disseminata 
forms a layer which surrounds the pelvic 
part of the urethra and is covered by the 
urethralis muscle, except dorsally 


cylindrical, and lie on either side of and upon 
the caudal two thirds of the pelvic urethra'’ 
(Fig 44-15) In a large boar they are about 
12 cm in length and 2 5 to 3 0 cm In width 
They are partially covered with a la^er of 
striated muscle (m bulboglandulans) and 
have a Iobulated surface Each gland has a 
large excretory duct which leaves at the deep 
face of the caudal part, perforates the dorsal 
wall of the urethra at the ischial arch, and 
opens in a cul-de sac covered by a fold of 
mucous membrane 

It is to be noted that these accessory glands are very 
small in animals which have been castrated early the 
bulbourethral glands may be only about 2.5 cm long In 
such subject* 


External Genitalia 

PENIS 

The penis resembles, in general, that of the 
ox (Fig 42-4) The sigmoid flexure is, how- 
ever, prescrotal The cranial part has no glans 
and is spirally twisted, especially in erection 
The external urethral onfice is slit like and 
situated ventrolaterally, close to the pointed 
extremity The penis w the adult boar mcas 
ures about 45 to 50 cm in length Its muscles 
resemble those of the bull The bulbospon 
giosus muscle is very strong, but short The 
retractor penis arises from the third and 
fourth sacral segments, its two parts run 
caudally and a little ventrally on each side of 


BUIBOURETHRAI GIANDS 

The bulbourethral glands are very large and 
dense (Fig 44-11) They are somewhat 


•When hardened in litu ihey are in great part three 
*lded with rounded edge* They are in contact with each 
other to a considerable extent and cover the urethra 
dorsally and laterally The urethrahs muscle partly cover* 
tbeir lateral surfaces 



l Dorsal a. of penis 1 dorsal a. and v of penis 2 corpus cavemosum penis 3 tunica albuginea A urethr-. 
K£T P ' 7 8 h°4y of pent* 9 p^tt.W HCZuZ.ZZ Z.L b T' 



42— PORCINE UROGENITAL SYSTEM 


the rectum to the perineum, where they 
reach the urethral surface of the perns, the> 
end on the ventral curve of the sigmoid 
flexure of the penis (Figs. 44-11 and 15) 


The prepuce has a narrow onficc, around 
which there are stiff hairs The cavity is vcn 
long and is partially divided by a circular 
fold into a caudal narrow part and a much 
wider crahial part The lining membrane ox 
the caudal part is papillated and is in close 
contact with the penis, it contains numerous 
lymph nodules, the largest of which occur in 
the fundus In the dorsal wall of the wide 
part there is a circular opening which leads 
into a cul de-sac, the preputial dwcrticulum 
(Fig 44-11) This pouch is ovoid in form 
(when distended) and vanes greatly in size 
in different subjects It extends for the most 
part caudally over the narrow 7 part of the pre 
puce Its cavity is partially divided by a nar 
row septum It usuall} contains decomposing 
unne and macerated epithelium, which have 
a charactenstic and very unpleasant odor 
Concrements have been found in it 

Oehmke (Sisson 1921) found that a cast of the pouch in 
a Yorkshire boar weighing about 227 kg measured 9 cm in 
length 12.5 cm in breadth and 6 cm in height inc 
opening into the prepuce will admit two fingers in tne 
adult but is ordinarily closed by folds of the lining mem 
hrane. The sac is much smaller in animals which w r 
castrated young and the opening is vertical and tanner 
caudad in them it is often empty or contains only a mue 


clear urine The pouch is elandless but contains many 
small limph nodules It is covered by a layer of striated 
muscle' tshlch Is mainly derived from the homoloeue of 
the protractor of the prepuce of ruminants 

MALE URETHRA 

The urethra has a very long pelvic part 
(about 15 to 20 cm long in the adu t) (Fig 
44-15) ft is covered (along with the pars 
disseminata of the prostate) by a thick 
urethralis muscle, except dorsally, where 
there is a dense fibrous layer Surrounding 
the mucous membrane there is a rich venous 
nlexus, which is regarded as a stratum 
cavemosum Outside of tins the pars dis 
seminata of the prostate is easily distinguished 
on cross section by its yellow color Ti e 
nrostatic ducts are numerous and small 
The ductus deferens and the excretory ducts 
of the vesicular glands have slit like openings 
close together in small diverticula on either 
side of the seminal colliculus The latter 
has the form of a round prominence A small 
masculme uterus may occur in the colliculus 
between the ducts, but it is often absent 
There is a distinct bulb at the root of the 
penis It has a dense covering, which m part 
resembles fibrocartilage The erectile tissue 
here is highly developed The cavernous 
spaces are large, and the trabeculae contain 
much smooth muscle, between the spaces 
there are numerous arteries The penile part 
is of small caliber and is surrounded by 
erectile tissue, which, however, does not 
extend to the extremity of the penis 


FEMALE GENITAL 


OVARIES 

The cylindrical ovaries are concealed in the 
ovanan bursa (Fig 44-12), owing to the large 
extent of the mesosalpinx They are more 
rounded than in the bitch and have a distinct 
hllus They may be situated at or near the 
lateral margin of the pelvic inlet, as m the 
cow, but their position is quite variable in 
animals which have borne young and they 
may be only 2 5 to 5 0 cm caudal to the kidney 
The surface commonly presents rounded 
prominences, so that the gland usually has 
an irregular lobulated appearance, the pro 
jections are large follicles and corpora lutea 
Mature follicles may have a diameter of about 
* to 8 mm, and corpora lutea may be found 
which measure 12 to 15 mm 

uterine TUBES 

The uterine (fallopian) tubes are long (about 
*5 to 30 cm) and less flexuous than in the 


ORGANS (Fig 42-5) 

mare The fimbriated extremity forms an 
ampulla and has a large abdominal opening 
The uterine end shades insensibly into tne 
small extremity of the horn (Fig 44-12) 


UTERUS 

The uterus presents several striking 
features The bodj is only about 5 cm long 
The horns are extremely long and flexuous, 
and are freely movable because of the large 
extent of the broad ligaments In the non- 
pregnant ammal they are arranged in numer- 
ous coils and appear somewhat like thick 
walled small intestine (Fig 44-12) They 
may be 1 2 to 1 5 m in length The extremities 
of the horns taper to about the diameter of the 
uterine tubes The neck is remarkable for its 
length (about 10 cm) and the fact that it is 
directly continued by the vagina without 
any mtravaglnal projection When slit open. 



1302 


PORCINE 



peculiar rounded prominences are seen on 
its interior some of these dovetail and oc 
elude the cervical canal They are continuous 
caudally with folds of the mucous membrane 
of the vagina The broad ligaments (lig 
latum uteri) contain a large amount of 
smooth muscle they also contain a large 
utenne lymph node near the ovary * In the 
dorsal part of the ligament the muscular 
tissue forms a rounded band termed the 
round ligament (hg teres uteri) In an adult 
sow of full size it is about 15 cm long Its 
cranial end forms a blunt projection and 
caudally it ends in the subserous tissue at 
the deep inguinal ring The medial layer of 
the broad ligament is continuous with the 
lateral ligament of the bladder 


VAGINA 

The vagina is about 10 to 12 cm long in a 
sow of medium size It is small in caliber 
and has a thick muscular coat which consists 
of circular fibers between two layers of 
longitudinal fibers The mucous membrane is 
plicated and united with the muscular coat 


•The changes in form and position of the uterus during 
pregnancy are similar to those mentioned later In the case 
of the hitch (p 1587) 


HGLKF 42- Genital organs of »w )W 
dorsal a «ew The sagittal vestibule 
vagina and cervix uteri are slit open 

1 Lips or vulva 2 glanv of clitoris 3 
vaginal vestibule 4 external urethral 
fice 5 vagina 5 cervix or uterus 6 body 
of uterus 7 horns of uterus one of which Is 
opened at 7 to show folds of mucous mem 
brane 8 uterine tube 8 abdominal oi’e'J 
Ing of tube 9 ovaries 10 ovarian bursa 1» 
broad ligaments of uterus J2 urinary bl*u3 
der (Fro n Fllenbcrger 1908) 


VAGINAL VESTIBUIE 

The vaginal vestibule Is about 75 cm m 
length The urethra opens into it On either 
side of the cranial part of the floor of the 
vaginal vestibule there is a cul-de sac and a 
deep groove leading back from it these are 
bounded medially by a longitudinal fold 
Longitudinal ducts (of epoophon (canals of 
Gartner) may be found opening cranial to 
the external urethral onfice 


External Genitalia 


FEMININE PUDENDUM 
(VULVA) 

The lips of the vulva are thick and are 
covered with a wrinkled integument The 
dorsal commissure is rounded but the 
ventral forms a long pointed projection (Fig 
44-12) The chloral fossa is about 2 cm 
cranial to the ventral commissure Above 
it the glans of the clitoris forms a pointed 
projection from which a mucous fold extends 
laterally and caudally on each side Then? is a 
deep central depression about halfway be 
tween the clitoral fossa and the external 
urethral orifice The latter is bounded on each 
side by a thick fold which extends causally 
for a variable distance Lateral to this fold Is 
a depression in which the ducts of vestibular 
glands open 



42— rOHCJNK tmOCJKMTAL ST STEM 


1303 


CUTOR1S 

The clitoris is lonR and Hexuaus, its Rians 
forms a pointed projection over the clitoml 
fossa 


FEMAtE URETHRA 

The urethra is about 7 to 8 cm Ions Its 
caudal part is fused with the vaRlna and pro- 
duces a corTcspondlnR elevation of the floor 
of the latter. 


mammary gIands 

The mammae arc usually 10 or 12 In number 
and are arranped in two rows, ns in the 
hitch Each teat commonly has two ducts 


BIBUOGRAPHY 


K '! and It Buffer JW-0 Tlw eubcmacufum tmkof 
the r<S *cm/j» J Anat 94 107.120 
Barone K and t Pavto*. I9T2 Lc* * alt tram tanculnt do tmtut 
Cnual c t-r t tot fcmeltot domeMiquo* Bull Soc Sel Vel Lyon 
\4 / 33 5a 

JUtrm- 11 C Fjuui *ni) l 1 Fnjwtt 1X1 I** vaHtoiux *.tn*ufn» 
do 1 jpi Jirll sxnltal the* la trult Bull Soc Sci V«t I yon 
No 3 ar-air 

*V }ty)A LeHrrtnc* Atlt» of the A«a«jmy«f rho Horae 
*nl the QtSttf Oorootilr Anlnult 2nd «d Clilrito Alewnder 

I t»» 

lllrnhergrt W and H Baum 1908 Ilindluchdcr Vrrgtctchcnden 
Anatomic dor Hauttlrtr Berlin ion Aufuit Hlrtchwafd 
Moyrn ) IMA lifilcriuf bi»n*rn JUr TunlJliw) dot PrapufUlbruJet* 
(*r» Schwotne* /bl \cl Med 55 473—192 
Neatillc li 1931 Dc lorsanc rlmiat do Ltirulc Bull Mu* Nation 
Km f ami fl* M 

Njficl Jl A Sthummrr and i. Scl/crlc 19u0 tehrbuch dcr 
Anatom e dor llautticio \ol II Bolin Paul Parey 
Nwnei Q and K (.ettt l 1 * O Arterial «uppl> to ttic cmtt.ili.i and 
• fretton senttaf ortatit cf twine Iowa State S Scl 44 93*120. 

N unrt Q and fl < ftiy |9'0 Blood trttolt cl the genlulu and 
•cento ry genital organ* of twine <Sut tetofa tfsmnllra) II 
V ont Iowa State J Sd 45 290 317 
Sitton S 1921 The Anatomy of the OometUc Animal*. 2nd td 
I InJadcIf'hia W B Saundert Company 



CHAPTER 43 


PORCINE 

ENDOCRINOLOGY 

by W G Venzke 


HYPOPHYSIS (PITUITARY GIAND) 

(Figs 43-1 and 46-4) 

The hypophysis lies m the dorsal part of the 
sella turcica A fibrous sheath of dura mater 
closely invests th£ gland and is fused with 
its capsule except where the diaphragma 
sella does not cover the hypophysis The pars 
nervosa extends caudally and is attached to 
the floor of the diencephalon by a thin infun 
dibular stalk The pars intermedia is attached 
to the neurohypophysis The pars tuberalis 
forms a thin sheet of glandular cells about the 
stalk. The pars distahs surrounds the neuro 
hypophysis An intraglandular cleft usually 
separates the pars distahs and pars intermedia 
The hypophysis of a six month old pig 
weighs approximately 025 gm The pars 
distahs comprises about 60 per cent of the 
hypophysis volume while the neurohy 



FIGURE 43-1 Hypophysis of porcine mid sagittal 
section. 

a. Infundibulum with adjacent pars tuberalis b infun- 
dibular cavity c hypophyseal cavity d, pars Intermedia 
andtuberals e pars distahs Stippled area is pars nervosa. 
(After Trautirunn and Ftebl&er 1952 ) 


pophysis accounts for approximately 25 per 
cent The other two lobes and the infufl 
dibular stalk account for the remainder 
The blood vessels associated with the 
hypophysis are similar to those of the cat or 
dog The internal carotid artenes are located 
lateral to the infundibulum These artene-S 
traverse the cavernous sinus and beneath the 
gland form a delicate network the rostral 
epidural rete mirabile The rete mirabile 
does not contribute much to the arterial 
supply of the gland The internal carotid 
artenes give nse to the cerebral artenal 
circle Of these artenes two rostral hypophy 
seal artenes can be traced beneath the optic 
chiasma to the pars distahs The neuro 
hypophysis receives its artenal supply 
from the basuar artery 

The venous drainage from the gland passes 
directly into the cavernous sinuses Portal 
veins are found coursing in the infundibulum 
from the hypothalamus to the pars distahs 
sinusoids 

The hypophysis is supplied by nerve fibers 
from the carotid plexus and from nuclei 
located m the hypothalamus The hypo 
thalamo hypophyseal tract fibers anse from 
the cells of the supraoptic paraventricular 
and lateral tuberal nuclei The lateral tuberal 
component is not well developed The distn 
bution of the hypothalamo hypophyseal tract 
is similar to that in the dog and cat 


THYROID GIAND 

The thyroid gland lies on the midhne 
ventral to the trachea just cranial to the 
thoracic inlet The lobes are red brown in 
color irregularly triangular in outline and 


1304 



1305 


43— PORCINE ENDOCRINOLOGY 


measure approximately 5 to 6 cm in ^length. 
The lobes are narrower from side to side than 
vertically. The gland weighs approximately 
5 gm in adults. The lobes are united for some 
distance on their ventral surface so that a 
distinct isthmus cannot be identified. I no 
dorsal surface of the gland is grooved longi- 
tudinally. Deeply the gland is related to the 
sides and ventral face of the trachea; dorsally 
the gland contacts the esophagus. 

The arterial supply is furnished by one or 
more branches arising from the right omo- 
cervical artery. The artery enters the gland at 
the caudal pole. The satellite vein leaving the 
caudal pole of the gland empties into the 
cranial vena cava. The lymphatic vessels 
drain into the cervical lymph nodes ine 
nerve supply arises from the autonomic 
nervous system. 


lulus directly from the aorta, or from the dor- 
sal abdominal or lumbar arteries. 

The right adrenal veins may empty directly 
into the caudal vena cava or into the dorsal 
abdominal vein. The left adrenal veins enter 
the dorsal abdominal or left renal vein. 

The lymph vessels pass to the renal lymph 
nodes but may go to the lumbar, cehac or 
rr^ininl mesenteric nodes. 


PANCREATIC ISIET TISSUE 

See Chapter 10. 


TESTES 

See Chapters 10 and 42. 


PARATHYROID GIAND 

Embryologists describe two pans of para- 
thyroid glands arising from branchial pouches 
III and IV in the developing pig. Macroscopic 
anatomists describe only one pair, the ex- 
ternal or cranial parathyroid glands. These 
glands are located far cranially to the thyroid, 
embedded in a portion of thymus approx- 
imately 3 cm from the paracondylar process 
near the branching of the carotid artery. 
They are located cranial to the omohyoideus 
muscle. The glands are globular or ovate in 
outline, measure 1 to 4 mm in length, 

0.08 to 0.10 gm and are pink m color. The 
glands are more firm than the surrounding 
thymus tissue. The glands are usually as- 
sociated with a septum just under the capsule 
along a small vein on the medial surface ot 
the thymus. 

No description can be found for the internal 
(caudal) parathyroid glands. They are prob- 
ably located caudal to the thyroid. 


ADRENAl GIANDS 

The adrenals (suprarenals) are long and 
cylindrical organs situated on the medial 
surface of the kidney cranial to its hilus in 
the perirenal fat (Fig. 42-1). Some glands 
^ay be triangular or ovate in outline. Both 
SJands lie in approximately the same plane, 
the right gland is attached to the caucmi 
v «na cava Its caudal pole contacts the right 
renal vein. The glands are reddish brown 
because of poor lipid content. The left gland 

usually longer and heavier than the right, 
{be glands in a 200-lb hog measure from 5 to 
1° cm in length, 1 to 3 cm in breadth and 0 5 
m 0.8 cm in thickness. Each adrenal weighs 
approximately 2 5 gm. J , 

l ne small adrenal arteries enter the adrenal 


OVARIES 

See Chapters 10 and 42 


INEAt GLAND 

In the pig the pineal gland lias a 

of 


INTESTINAL MUCOSA 

See Chapter 10. 


bibliography 

I 1951 A eytochomid smdy of l.pid. >9 . 01 !.- ovorlos 

^ ar ^ e “ rin ^ , ^g0y I, .^ S thc C ultrastt^ciijr8 o^fothde^and^lsolaied 

B) "3„ VS™ «*» p"" 1 ™ *• Zellf0 “ h 82 17 

SS r‘SL« 1. comparand mo.pl.oMca' «.peci. Arch 

£ SSSS. in lie P* Am J Physiol ,U> 
andj R Cblon 1007 T.rtcoU. dosoloprn.o! In mini 
oMmn mSomopic nW-ljg 

S hypophyseal sulk or ..In, Jh Mforsch.. 07 

77 29-57 



CHAPTER 


44 


PORCINE 
HEART AND 
ARTERIES 

by N. G. Ghoshal (with Blood Supply to 
Brain by B S. Nanda) 


PERICARDIUM 


fr Jm a ? rd ' um ,s a ‘tached to the sternum 
xmhmH POm , t ? PP ° slle ,hc "unlnbaaferas the 
xiphoid cartilage, and also to the sternal part 


diaphragm It has extensive contact 
with the lateral thoracic wall from the second 
intercostal space to the fifth nb 


HEART 


The heart (cor) is small in proportion to the 
body weight (0 23 to 0 28 per cent), especially 
in fat animals Its weight in a large adult is 
usually less than a pound (240 to 500 gm) !t 
Mt r °h\f 10rt ' 3 " d bl T. When hMdened m 

situ ft Is compressed dorsoventrally The 
ventral or auricular surface is only moderately 

fr°„mTh (F ' g 4 1r 11 “ oceri,es 2S2 

from the second stemebra to the cranial part 
of the seventh one The paraconal mter- 
ventr.cu'ar groove is on Its left part (Fig 
44-2), and is almost parallel with the left 
ventricular border The dorsal or atnal sur 
lace is more convex (Fig 44-3) The sub- 
simtosal interventricular groove runs ob 
liquely across this surface (Fig 44-4) 
it beguts ventral to the end of the caudai 
vena cava and extends to the left ventricular 
border There is often a so called mtermedi- 
ate groove on the left ventricular border (Fig 
44-2), It may extend to the apex, but it Is fre 
quently small and is sometimes absent The 
apex is blunt and is almost median, ft overlies 
1306 


P K r ‘ ° f sevemh s'vmebra, and 

IS about 5 to 6 mm from the sternal part of the 

tended^ hp ^ the ventncles^e dis- 
Seis corS) Th n ° ,Ch at ,' he apex 

aSnde U marl 2E Vemral border of «« left 
llan/i cu ? ? by severa! notches (Fig. 44- 
one S Situa * ed at a tower level than the right 

leftVzygo^nTs?" thG ° nflce of the 
caudal vena civ! to that of lhe 

valvular fob! S h are s 0 M ra ted by a 

muscles radiate fmm o f The Parnate 
and form a h g h fy deyelon H C ‘ ' ern,,nal 
auricle The oral '° P ' d >- ,he 

large septomsrgmal Irabeeol, fa l?'" 15 * 
ventncle ““oecuia in the nght 

«fhS"t r u;fS? > ,hl*;r i ?'rtcie;of V .nepfa'’’h° r t b ' tmU ‘ C ‘ ,lar 

greater development of the right ventrical* ntMln * ,he 



44-PORCINf. Ilf ART AND ARTERIfS 


1307 


FIGURE 44-1 Heart of pig, auricular (left) surface 

1 Descending aorta 2 left subclavian a 3 brachiocephalic 
trunk 4 bg artenosum 5 pulmonary trunk G right auricle 
7 leftauncle 8 left \ ena azygos 9 left pulmonary a 10 left 
pulmonary v 11 right ventricle 12 great cardiac v 13 
paraconal interventricular branch 14 left \cntriclc 



I Hi te> ft 



d ' C m „ lmctlo , us lctra , cnrtlacv j n panreoaal interventricular groove 3 in, ermcdlate branch in stalled in.rnar 
’ Uotlv * 4 apex 



1308 


1 ORCINE 


\ IGURE 41-3 Heart of pig atrial (right) surface 

1 Descending aorta 2 left subclavian a. 3 brachiocephalic 
trunk 4 he arteriosum 5 pulmonary trunk (daplcal lobar a un 
marked above #6) 6 pulmonary vv 7 left vena azygos B caudal 
vena cava 9 cranial vena cava 10 right atrium 11 great cardiac 
v 12 coronary sinus 13 right coronary a 14 middle cardiac v 
15 subslnuosal Interventricular branch 16 left ventricle 17 
right ventricle 


outer surface layer and layeiuf ridges) sponge and basket outer portion common to both ventricles and a deep bulbo- 
Uyers. The outer surface layer (cf the cortical layer) corre- spiral muscle conf ned to the left ventricle. The sponge and 

sponds to the vortex layer of Tandler (1913) or the com basket layers make up the deepest layer of each ventricle 

b ned sinosp nil and superficial bulbospiral layers of Mali Including the papillary muscles trabeculae cameae sep- 
(1911). The layer of ndges together with the muscular tomarginal trabecula and the longitud nal muscle of the 
septum forms the adult m ddle layer which includes an right ventricle. 



FIGURE 44-4 Heart of pig atrial surface 



lto5 Pulmonary vv 6 left pulmonary a. 7 S branchesof right pulmonary a. 9 it 
groove 11 vessels and fat in subs nuosal interventricular groove 12 apex. For Post. 




44 -PORCINE HEART AND ARTERIES 

ARTERIES 


1309 


The pulmonarj trunk presents no remark- 
able features 

The aorta resembles that of the horse and 
ox in its course and relations, but the arch is 
much more strongly curved The left sub 
clavian artery and the brachiocephalic trunk 
anse separately from the aortic arch 


Branches of the Ascending Aorta 

1 The coronarj arteries, right and left, are 
almost the same size The left coronarj arterj 
supplies the greater part of the wall of the left 
ventricle and auricle, including the inter 
ventricular septum, by means of its circumflex 
a nd paraconal inter\entricular branches The 
circumflex and subsinuosal inter\entricular 
branches of the right coronary artery supply 
the wall of the nght ventricle and the auricle, 
deluding the rest of the interventricular sep 

turn (Schwarze and Schroder, 1964) 

*I ord '"e ‘0 Christensen and Campetl (1959) the atrial 
few k* , ansm 8 from the coronary arteries arc relatively 
chamk se k eral sma h vessels nourish the dorsal heart 
the W? r J Va,,s large ventral left atrial artery supplies 
the Ur, *h e valvular area of the aorta the base of 

‘Hte (mi i atrta and the wall of the cranial vena cava 
base of t'h r,R,lt a,na11 Br * er > supplies the right atrium the 
veins nna* ^ ranial v *na cava the walls of the pulmonary 
tecy usu-jti ” e Cauda * vena cava. The ventral right atnalar 
n ghtanprvi anses ln comm °n with the accessory ventral 
htteratn-i Snlri nsically these arteries also vascularize the 
frsclcle I 8ep ‘ Um l he A V node and the atrioventricular 
c °ronarv a 61 XV| ^ 1 numerous small branches from the 
'be duini * erie * The dorsal right atrial artery nnses from 
eorooarv an n ^ lIlir ^ circumflex branch of the right 
w beft arte ei ? ^hnstensen and Campeti 1959) The dor 
v *ntral arte* * re ^ Uenl ly originates with the corresponding 
Um the aorI7f. an ^ 7 supplies the ventral side of the left atn 
efreumflex kf Va J ve re 8ion and the pulmonary veins The 
tuning i n °f the nght coronary artery ends by 
*trtai surface e f 8u * >sinu °sal interventricular groove of the 
It gives off a large subsinuosal 
Ventricle &u ^ l T rane h to the central portion of the right 
branches. Thp ly * nR Us mus culature by numerous small 
°f the Paracon^i e « Pta ' artery arises at or near the junction 
°f the lefj 1 'nterventricular and circumflex branches 
‘'Plum h y aar V ar tcry It supplies the interventncular 
terminal i„ crous branches The left circumflex branch 
Mnus numerous small branches near the coronary 

l>ra< * ,0 ccphuhc trunk arises first 
tr al to thf, r ^ arc h and passes cramally ven 
0fft kenpv! gc , ? t0 the first rib Here it gives 
the 1 SUbc lvian art ery 

rhlt nI!!, of the right subclavian artery 

fc ri' in c\Z Y Un .^ 0r distally from the brichioce- 
« aL^jgbcster White pigs has been reported by 

J^dit suW'h!? 0611 * 111 * 10 trunk dnidcs into tlie 
ln mkThfi c ^£ and the bicarotid 


ratio between the preceding 


vessels vanes considerably Differences 
exist in the pattern of branching between the 
right and left subclavian arteries 

3 The left subclatian artery arises inde 
nendently from the aortic arch just doisal to 
the brachiocephalic trunk It cunes cramally 
and ventrally and leaves the thoracic cavity at 
the cranial thoracic aperture (inlet) by wind 
ing around the cranial border of the first rib 
The branches of the left subclavian artery are 

aS a f °The S costocerncal trunk consists of the 
f “ B ahl“' «), «Ve e s C off thefirst (left) 

iiasssi 

SSSs 

costal space, SU W B “ *? ' h gives of f the 
rhomboideus and tropezius n gi 

and anastomosj jj* . tl]e j foramen and 

Then H passes through the a a ^ vertebral 

—by ^.ngCthTh^rtebra, artery of 

the opposite side . pme rges dorsallj 

The descending branch Supplies the obit 
from the alar j ca udalis, rectus 

quus capitis T^amr and minor, semi 

“^Lc^s ands^nius^pu, js 

usually arises separately medl0 l to the 

artery (Koch 1970) It Tbc CnK ht) 

first nb and ascends s by a common 

superfic.alcerv.calwfon udij Y , d arlcry , 

trunk with the (g ;^ icaltrunk ^ 

thus forming th f th> arte ry arises, medial 

e The internal th ® r fhi \ entml aspect of the 
to the first nb< It courses caudally 
subclavian (Fig thoracis It gives off the 

under the tmnsvemus tho^ ^ 5C4cn 

tentral intercostal g „ lt b the cor 

intercostal spaces f Jones (except 

responding dors; ' ,ercostal artery «b' ch 

the first dors-il r . , a j the second dorsal 

^rsufa^Vo^no; extend hc,on ,hc 


rORCINE 


1310 

middle of the corresponding intercostal space 
and therefore, it does not anastomose with 
the respective ventral intercostal branch) 
Medially it gives off the perforating branches 
(pig 44-IO) which, in turn, supply the trans 
versus thoracis the sternal lymph nodes and 
the sternum (rami sternales) Caudal to the 
perforating branches arise delicate twigs 
which after piercing the pectoral muscles 
supply the mammary complex and the skin 
(rami mammarn) Medial to the costal arch 
and at the level of the sixth intercostal space 
it divides into the musculophrenic and cranial 
epigastric arteries (Fig 44-10) The musculo* 
phrenic artery is relatively large and gives off 
the ventral intercostal branches to the sev 
enth and eighth occasionally the sixth inter 
costal spaces (Kahler, 1960) In addition it 
releases several small branches to the costal 
part of the diaphragm and the trans versus ab- 
dominis The cranial epigastric artery con 
tinues the internal thoracic to the abdominal 
region supplying almost the cranial two 
thirds of the rectus abdominis It gives off the 
ventral Intercostal and ventral costoabdomi 
nal branches which after ascending in the 
respective intercostal spaces and caudal to 
the last rib, anastomose with the correspond 
ing dorsal intercostal and dorsal costoabdomi 
nal arteries respectively During its course it 
releases several small branches the medial 
ones vascularize the rectus abdominis pec 
toralis ascendens, obliquus extemus ab 
dommis, cutaneus trunci the mammary 
glands, and the skin around the xiphoid 
region The lateral branches supply the trans 
versus abdominis and, after piercing the 
reStus abdominis, they ramify in the cutaneus 
trunci and skin of the cranial abdominal 
region 

The right subclavian artery, after arising 
from the brachiocephalic gives off the follow 
ing 

a. The vertebral artery has a similar course, 
area of vascularization, and relationship as 
that of the left artery Close to its ongin It re 
leases a slender first (right) dorsal intercostal 
artery 

b The dorsal scapular artery also has iden 
tical relationships to that of the left side 

c The deep cervical artery usually does not 
give nse to the supreme intercostal and, there 
fore, a costocervical trunk is absent on the 
right side (Koch 1970) 

d The supreme intercostal artery arises 
separately from the right subclavian and gives 
ongin to the third, fourth, and fifth intercos- 
tals Occasionally it anses from the deep cer 
vical 

e The (right) superficial cen ical artery has 
been described with the corresponding left 
artery 

f The internal thoracic artery of the ngbt 
side has an identical ongin, course, branching 


pattern, and area of vasculanzation as that of 
the left side 

COMMON CAROTID ARTERIES 

At the level of the first rib, following the 
ongm of the nght subclavian, the brachio- 
cephalic trunk usually continues for a short 
stretch as the bicarotid trunk 

The length of the brachiocephalic trunk and the bUaro- 
tid trunk varies considerably between specimens The ratio 
between them Is on an average 3 1 (Smollich and BerR 
1960) Occasionally the right subclavian artery arises In 
common with the bicarotid trunk from the brachiocephalic 
Sometimes the left common carotid artery arise* separately 
In the absence of a bicarotid trunk In that case the right 
common carotid artery arises together with the right sub- 
clavian. 

The common carotids separate into the right 
and left artery near the cranial thoracic aper- 
ture (inlet) Each artery then continues to as- 
cend in the neck along the ventrolateral as 
pect of the trachea, accompanying the in temal 
jugular vein laterally, the vagosympathetic 
trunk dorsomedially, and the recurrent latyn 
geal nerve ventrally, within the carotid sheath 
The common carotid artery terminates, m a 
variable manner, into the external carotid, oc- 
cipital, and internal carotid arteries in the 
cranial deep aspect of the jugular furrow The 
branches of the common carotid artery are 
(Fig 44-5) 

1 The cranial thyroid artery arises at a vari 
able level, frequently near the third tracheal 
nng It gives off the esophageal, tracheal, and 
pharyngeal branches During its course to the 
thyroid gland it gives off muscular branches to 
the thyrohyoideus, stemothyroideus, and cri 
coibyroidcus Its caudal laryngeal branch 
passes caudally, accompanying the caudal 
laryngeal nerve Sometimes the cranial thy 
roid artery is only found on the left side 
(Becker, 1960) It anastomoses with the cau 
dal thyroid artery, which is usually a branch 
of the thyrocervical trunk on the nght side, on 
the left its ongin is extremely vanable 

2 The cranial laryngeal artery anses close 
to the terminal divisions of the common caro- 
tid It gives off the esophageal, tracheal, phar- 
yngeal and laryngeal branches It enters the 
larynx and divides into a medial and lateral 
branch, the medial branch supplies the in 
tnnsic laryngeal muscles and the mucous 
membrane The lateral branch is relatively 
large, coursing ventrally and laterally on the 
thyrohyoideus It supplies the omohyoideus 
stemohyoideus and parotid gland 


EXTERNAL CAROTID ARTERY 

(Fig 44-5) 

The externa! carotid artery anses from the 
common carotid artery medial to the jugular 




1 Common carotid. a. 2 cranial thyroid a 3 pharyngeal branch 4 caudal laryngeal branch 5 common trunk of 6 and 
12 6 occipital a 7 caudal meningeal a. 8 muscular branch 0 sertebrala 10 occipital branch II descending branch 
12. internal carotid a 13 condylara 14 stylomastoid a 15 external carotid a 16 linguala. 17 ascending palatine a 
IB ascending pharyngeal a ID ^descending pharyngeal a. 20 submental a. 21 mental branch®* 23 muscular 
branches 24 facials 25 caudal auncular a 26 lateral auricular branch 27 intermediate auricular branch 28 medial 
auricular branch 2D deep auricular a 32 34 parotid branches} 35 superficial temporal a 36 transverse facial a 37 
masseteric a 38 dorsal branch 39 sentra! branch 40 maxillary a. 41 middle meningeal a 4° mand bular alveolar a 
43. pterygoid branch 44 mental branch 45 ca dal deep temporal a 46 buccal a 47 muscular branch 48 aLtoanglcof 
eye 49 anastomotic brand 50 mandibular labial a. 51 maxillary labial a 52. a to ancle of mouth 53 external ophthal 
mica- 54 rostral meningeal a 55 malar a 56 deep branch of infraorbital a 57 maxilloincisive a (dental branches) 
58 superficial branch o* 56 (lateral nasal a) 59 descending palatine a lilt 


1312 


PORCINE 


process During its course it describes an S 
shaped curve and gives off the following col 
laterals „ , , , 

1 The lingual artery anses from the medial 

aspect of the tip of the jugular process medt 

al to the digastncus, following the hypoglos 
sal nerve It enters the tongue after passing 
medial to the styloglossus It releases the fol 
lowing branches 

a. The penhyoid branches 
b The ascending palatine artery, after 
coursing rostromedially medial to the stylo- 
hyoid, supplies the soft palate and its muscu 
lature 


trolateral aspect of the external carotid It is 
covered laterally by the ventral end of the 
jugular process It supplies the digastncus 
and pterygoideus mediahs and releases the 
following branches 

a. The pharyngeal branch supplies the stylo- 
glossus pterygoideus medialis, and the lateral 
pharyngeal wall, including the soft palate 
b The glandular branches supply the man 
dibular gland and some of them, after pierc- 
ing same, ramify m the parotid gland 
c The muscular branches arise near the 
mandibular angle and supply the masseter 
and the muscles arising from the mental 


c The muscular branches for the thyro- 
hyoideus, stylopharyngeus, stylohyoideus and 
digastncus 

d The ascending pharyngeal artery, after 
crossing the ceratohyoid, arises from the dor 
sal aspect and divides into palatine and 
pharyngeal branches They supply the pala 
tine and pharyngeal muscles The ascending 
pharyngeal artery may be double 
e The descending pharyngeal artery anses, 
at the same level of the preceding artery, from 
the ventral aspect of the lingual It runs ven 
trally along the lateral aspect of the genioglos 
sus and after piercing same, arrives at the 
ventral pharyngeal wall Occasionally, it 
gives off a strong laryngeal branch supplying 
the pharyngeal mucous membrane about the 
epiglottis (Becker, 1960) 

f The dorsal lingual branches are small, 
entering the tongue on the medial aspect of 
the styloglossus They ramify toward the dor 
sum of the tongue They often anastomose 
with similar branches of the opposite side 

g. The submental artery arises at the level 
of the fourth cheek tooth U ramifies in the 
genioglossus, mylohyoideus and geniohy- 
oideus It passes toward the mental angle on 
the genioglossus and enters the mandible 
through the medial mental foramen After 
anastomosing with the mandibular alveolar 
artery it supplies the mandibular incisor 
teeth (Becker, 1900) 

h The sublingual arterj is slender, arising 
from the submental artery shortly after its 
origin It may also arise from the lingual be- 
fore the origin of the submental artery It vas 
culanzes the geniohjoideus gemoglossusand 
mylohjoidcus the sublingual gland, and the 
mucous membrane of the floor of the mouth, 
including the frenulum linguae 

1 The deep lingual artery is the continuation 
of the parent \ essel following the origin of the 
submental arteiy It passes dorsally along the 
deep aspect of the stjloglossus and runs to- 
ss ard the tip of the tongue, describing a flexu 
ous course It anastomoses with its fellow of 
the opposite side about the frenulum linguae 

2 The facial arterj’ arises, immediately ros 
tral to the ongin of the lingual, from the ven 


angle 

d The submental artery may anse from the 
facial 

3 The caudal auricular artery anses deeply 
from the external carotid, rostral to the jugular 
process and caudal to the stylohyoid It as 
cends between the parotid gland and the tern 
poral crest, gives branches to the parotid 
gland, both parts of the cleidocephalicus, and 
the tendon of insertion of the stemomastoide 
us Its end branching is quite variable, ter 
minatmg in a pad of fat, it divides into the 
lateral, medial, and intermediate auricular 
branches destined to supply the auncular 
muscles and cartilage It may give off the 
caudal meningeal artery (instead of the oc 
cipital artery), which enters the cranial cavity 
through the mastoid foramen (Sisson and 
Grossman, 1953) The deep auncular artery 
Is the continuation of the parent vessel It 
supplies the temporalis and anastomoses with 
the superficial temporal 

4 The parotid branches are slender, arising 
in variable numbers from the external carotid 
They supply the parotid gland. 

5 The superficial temporal artery is the last 
branch of the external carotid Frequently it 
arises with the transverse facial by a short 
common trunk, which soon separates It 
courses dorsally and rostrally lateral to the 
zygomatic arch and gives branches to the 
temporalis and aunculares ventrales It passes 
beneath the zygomaticoauncularis where it 
anastomoses with the deep auricular artery 
and later ramifies in the rostral, dorsal, and 
caudal auricular muscles The rostral auricu- 
lar artenes, after arising from the superficial 
temporal, supply the adductors and the medial 
surface of the auncular cartilage 

According to Sisson and Grossman (1953), 
the superficial temporal artery is small or 
may be absent In the latter case the rostral 
auncular and transverse facial artenes anse 
separately from the external carotid artery 

6 The transferee facial arterj arises to- 
gether with the superficial temporal This 
slender vessel, after coursing around the ar 
ticular process of the mandible, runs rostrally 
on the surface of the masseter It gives off 



4 1 -PORCINE HEART AND ARTERIES 


1313 


dorsally the articular branch to supply the 
temporomandibular joint capsule Sometimes 
it detaches ventrally the masseteric arterj, 
which enters the dorsal part of the masseter 
muscle (Becker, 1960) After releasing sev- 
eral small branches to the masseter, ventral to 
the eye, the transverse facial ends in dorsal 
and ventral branches The dorsal branch rami- 
fies in the zygomaticus, malaris, orbicularis 
oculi, and the inferior eyelid, while the ven- 
tral branch is destined to supply the masseter 
along its rostral border 
7 Tiie maxillary artery is the rostral con 
tmuation of the external carotid beyond the 
origin of the superficial temporal or common 
trunk for the latter and the transverse facial 
artery It pursues a flexuous course between 
the pterygoideus medialis and pterygoideus 
lateralis, accompanied laterally by a homon 
ymous vein, through the pterygopalatine 
fossa Near the rostral end of the latter, it 
ends in the infraorbital and descending pala 
tine arteries During its course through the 
pterygopalatine fossa it gives off the follow 
ing 

a The middle meningeal arterj, after 
arising from the medial aspect of the maxil 
lary, passes caudomedially along the medial 
aspect of the tympanic bulla As a variation, it 
may arise from the caudal deep temporal ar- 
tery (Becker, 1960) During its course, it sup 
plies the pterygoideus medialis and courses 
between the preceding and the pterygoideus 
lateralis The branch to the rostral epidural 
rete mirabile enters the cranial cavity through 
the foramen lacerum and concurs in the for- 
mation of the rostral epidural rete mirabile 
b The caudal deep temporal arterj arises 
from the dorsal aspect of the maxillary and, 
after piercing the pterygoideus lateralis, 
courses toward the mandibular notch, medial 
to the zygomatic arch It usually gives off »he 
masseteric arterj near the mandibular notch 
which, after traversing same, mainly supplies 
the masseter In addition, it releases the 
pterjgoid branches (some of them anse di 
rectly from the maxillary) supplying the ptery 
goideus lateralis and temporalis The caudal 
deep temporal artery courses deep to the tem 
poralis, inside the temporal fossa and anasto- 
moses with the deep auricular artery (Becker, 
1960) 

c The mnndibular alveolar arterj, after 
arising close to the origin of the parent vessel, 
passes rostro ventrally between the mandibu 
lar ramus and the pterygoideus medialis Be 
fore entering the mandibular foramen it sup- 
plies the preceding muscle and the mylohy- 
oideus While coursing within the mandibular 
canal together with the homonymous vein 
and nerve, it releases a senes of dental 
branches to the cheek teeth It emerges 
through the lateral mental foramen, where it 


gives ofT the mental branches ramifying on 
the mandibular lip It continues through the 
alveolar canal and, after anastomosing with 
the submental artery through the medial 
mental foramen, supplies the incisor teeth as 
the mandibular incisive arterj (Becker, 1960) 
d The buccal arterj is the largest collateral 
branch of the maxillary, partly compensating 
for the relatively smaller facial artery After 
arising dorsally from the parent vessel it 
runs toward the pterygopalatine fossa, ac- 
companying the satellite vein Following its 
ongin, it lies on the dorsal aspect of the ptery 
goideus medialis, which it supplies Here, it 
releases a long rostral deep temporal arterj 
for the temporalis Before coursing between 
the maxillary tuber and the rostral border of 
the mandible it gives off an anastomotic 
branch which, after passing ventrally and 
caudally along the rostral border of the mas- 
seter, joins the facial artery After giving off 
the anastomotic branch it passes along the 
lateral surface of the masseter and, at the ros- 
tral border of the latter, it divides into end 
branches The angulans oculi artery ascends 
to the temporal process of the zygomatic bone, 
then turns rostrally and, after coursing along 
the facial crest, it supplies the malans and 
orbiculans oculi It releases a small medial ar- 
terj to the inferior eyelid (a palpebrahs in- 
ferior medialis ) The other branches of the 
buccal artery supply the muscles of both max- 
illary and mandibular lips The angulans oris 
artery passes rostroventrally and enters the 
orbiculans ons at its caudal end The man- 
dibular labial artery supplies the ventral buc 
cal glands, the depressor labu mandibulans, 
and the orbiculans ons The maxillary labial 
arterj supplies the dorsal buccal glands, the 
orbiculans ons, and the depressor labn max 
lllans 

e The external ophthalmic arterj anses 
slightly rostral to the ongm of the buccal 
This is the mam artery supplying the eye and 
its adnexa It passes rostral to the pterygoid 
crest, following the maxillary nerve laterally 
Here, it releases the rostral meningeal artery 
which supplies the penorbital fat and gives off 
the branch to the rostral epidural rete mirabile 
The latter passes through the foramen orbito- 
rotundum and enters the cranial cavity, where 
it concurs in the formation of the rostral epi- 
dural rete mirabile Dorsally it gives off a 
strong supratrochlear arterj which, after 
piercmg the penorbita, courses along the rec- 
tus lateralis It passes dorsally, and crosses the 
rectus dorsalis and levator palpebrae supen- 
ons, which it supplies After again piercmg 
the penorbita it becomes the medial arterj' of 
the superior ejelid (a palpebrahs superior 
medialis ), coursing along the rostral aspect of 
the zygomatic process of the frontal bone It 
supplies the orbiculans oculi and frontoscutu- 



PORCINE 


1314 

Ians The external ethmoidal arter> is the con 
tinuation of the parent vessel and enters the 
cranial cavity through the ethmoid foramen 
It ramifies in the ethmoid bone, the adjoining 
parts of the nasal septum and the dorsal 
concha. In the ethmoidal fossa it forms an 
ethmoidal rete with the internal ethmoidal 
artery ( ramus anastomoticus cum a oph 
thalmlca interna ) The supraorbital artery 
arises from the parent vessel and supplies the 
periorbita and the orbital periosteum It sel 
dom emerges through the supraorbital fora 
men of the frontal bone supplying the neigh 
boring structures (Nickel and Schwarz 1963) 
The lacrimal artery passes between the rectus 
dorsalis and medialis, divides in two, and sup- 
plies the lacrimal gland- It gives off the lateral 
arter) to the inferior eyelid (a palpebrahs 
inferior lateralis) and the lateral artery to the 
superior eyelid ( a palpebrahs superior lat 
erahs') The muscular branches lie on the dor 
sal aspect of the optic nerve, medial to the 
rectus medialis Soon it divides into long pos- 
terior ciliary arteries and posterior conjune- 
tnal arteries. The central artery of the retina 
arises either from the muscular branches 
shortly before their terminal branches or, 
frequently, from the long posterior ciliary ax 
tenes (Becker, 1960) It enters the optic nerve 
slightly caudal to the eyebalL 
f The malar artery arises directly from the 
maxillary in the pterygopalatine fossa(Becker, 
1960) Shortly after its origin it releases the 
frontal branch which, after coursing outside 
the periorbita and following the ventral border 
of the orbit, reaches the medial angle of the 
eye, where it gives off the medial artery of the 
inferior eyelid (a palpebrahs inferior me- 
dialis} It anastomoses w ith the corresponding 
lateral artery and supplies the malans and 
orbicularis oculu The frontal branch continues 
towards the medial angle of the eye and disap- 
pears in the conjunctiva after giving off a 
branch to the levator labii maxillans, which 
anastomoses with a branch of the infraorbital 
artery (Becker, 1960) The malar artery pierces 
the periorbita and gives off the artery of the 
third eyelid (a palpebrae tertiae ) While 
coursing vcntnl to the obliquus ventralis it 
supplies same and the well-developed deep 
gland of the third eyelid. The antenor conjunc- 
tival arteries are the end branches of the 
parent vessel, supplying the conjunctiva. The 
dorsal nasal artery is small and slender, it 
anses from the malar near the medial angle of 
the eye 

g. The infraorbital artery arises from the 
maxillary at the rostral end of the pterygopala 
tine fossa, as one of its end branches It enters 
the infraorbital canal through the maxillary 
foramen in company with the infraorbital 
nerve Within the canal it gives several dental 


branches to the maxillary cheek teeth and, 
after coursing inside the maxillomcisive 
canal supplies the canine and incisors Fol 
lowing its emergence through the infraorbital 
foramen it splits into several branches supply 
uig the facial muscles According to Becker 
(1960), it gives off a deep and a superficial 
branch The deep branch is destined to supply 
the maxillary lip muscles The superficial 
branch also supplies the snout, but from its 
course and relationship it corresponds to the 
lateral nasal artery Some of the branches ter 
minate in the maxillary lip, supplementing the 
area of vascularization of the maxillary labial 
artery 

h The descending palatine artery is the 
other terminal branch of the maxillary at the 
rostral end of the pterygopalatine fossa. Short- 
ly after its origin it releases the sphenopala- 
tine artery. The latter may originate directly 
from the maxillary, somewhat caudal to the 
origin of the greater palatine artery It enters 
the nasal cavity through the sphenopalatine 
foramen and ramifies m the mucous mem- 
brane of the nasal septum, olfactory mucosa, 
and the mucous membrane lining the dorsal 
and ventral nasal conchae (aa nasales cau- 
dales, laterales et septi ) Inside the nasal 
cav lty it anastomoses with the branches of the 
greater palatine artery During its course 
toward the caudal palatine foramen the de 
scending palatine artery is related to the ten 
tral aspect of the infraorbital nerve, giv in g off 
the lesser palatine artery. The latter is small 
and sometimes is absent After coursing be- 
tween the pterygoid process of the palatine 
bone and the maxillary tuber it enters the soft 
palate, ramifying inside same The greater 
palatine artery continues the descending 
palatine after the origin of the lesser palatine 
artery It courses rostrally through the palatine 
canal and the palatine groove, giving off 
numerous branches to the mucous membrane 
of the hard palate It gives off an anastomotic 
branch caudal to the palatine fissure, anasto- 
mosing with its fellow of the opposite side It 
enters the nasal cavity through the palatine 
fissure, suppbes the nasal mucous membrane, 
and finally anastomoses with the caudal nasal 
artery Sometimes both greater palatine ar 
tenes anastomose at the intenncisive fissure 
and frequently ramify in a variable manner 
inside the snout 


INTERNAL CAROTID ARTERY 
(Fig. 44-5) 

The internal carotid artery usuallyarisesby 
a short common trunk with the occipital It is 
larger than the occipital artery, unlike that of 
other domestic animals It passes dorsal! y 



44- PORCINE HEART AND ARTERIES 


1315 


toward the jugular foramen, medial to the 
tympanic bulla, supplying the dura mater At 
the tip of the jugular process the occipital 
artery releases the condylar artery, which 
is sometimes represented by two vessels 
(Becker, 1960) The condylar artery divides 
in the condyloid fossa, one of these branches 
enters the cranial cavity through the hypo 
glossal foramen, while the other enters 
through the jugular foramen, contributing 
to the caudal epidural rete mirabile Accord 
ing to Becker (1960), the stylomastoid artery' 
may arise from the condylar or from its end 
branches This artery accompanies the facial 
nerve and reaches the middle ear after 
traversing the facial canal The caudal 
meningeal artery arises from the occipital 
at the level of the wing of the atlas and 
enters the cranial cavity via the temporal 
canal It ramifies in the dura mater The 
occipital artery anastomoses with the verte 
bral inside the atlantal fossa 

BLOOD SUPPLY TO THE BRAIN 

(Fig 44-6) 
by B S Nanda 

The brain of the pig receives its blood supply 
from the internal carotid and basilar arteries 
The rostral epidural rete mirabile is formed 
by the branches of the maxillary and internal 
carotid artenes 

AccordtngtoDaniel etal(1953) the interna] carotid artery 
does not participate in the rete formation and instead is re 
placed by the ascending pharyngeal artery Becker (1960) 
Nickel and Schwarz (1963) and N A V (1968) do not agree 
with the aforementioned authors 

The rete is a network of fine arterioles situated 
in the cavernous sinus around the lateral as 
pect of the hypophysis The retia of either side 
are connected with each other rostrally and 
caudally The rostral connecting branches be 
tween the retia are very weak The interanas 
tomosing network connecting the retia of ei 
ther side is located in the intercavernous sinus 
and represents a plexiform formation which 
seems to be homologous with the caudal inter 
carotid artery generally present in the dog cat, 
horse, and man The branches forming the 
interanastomosing network between the retia 
of either side may be termed “caudal inter 
carotid branches However, it has been 
termed ' intercarotid plexus* by Flcschsig 
and Zintzsch (1969) From the above forma 
tion a number of fine vessels are sent to sup- 
ply the pars nervosa pars intermedia and 
infundibulum of the hypophysis, which may 
be termed the caudal (inferior) hypophysial 
arteries 


The middle meningeal artery (a branch of 
the maxillary artery) enters the cranial cavity 
and cavernous sinus through the foramen 
lacerum and concurs in the formation of the 
rostral epidural rete mirabile by means of a 
branch 

Tills has been referred to differently by various workers 
The middle meningeal artery given off by the anastomotic 
branch has been referred to by Canova (1909) Schmidt 
(1910) Heeschen (1958) and Schwarz (1959) as the proxi 
mal retial branch in ruminants Becker (1960) called it the 
middle meningeal artery 

The rostral meningeal artery (a branch of 
the external ophthalmic artery) passes 
through the foramen orbitorotundum to con- 
tribute m the formation of the rete by means 
of a branch In the pig the contribution by 
the branches of the maxillary artery is very 
small in comparison to the contribution m 
the case of cattle, sheep, goats, and cats 

The internal carotid artery gives off retial 
branches as it enters the cavernous sinus and 
joins with the retial branches from the above 
mentioned branches of the maxillary artery to 
complete the rete In the cavernous sinus the 
retial network converges rostromedially to re 
join the artenal trunk 

The term cerebral carotid artery has been used by various 
workers for the artenal segment formed by the convergence 
of the ref iaf branches forming the rete However the term 
internal carotid artery has been advocated by N A V (1968) 
The latter is justifiable due to the fact that the rete so dc 
senbed and contnbuted to by previously mentioned vessels 
is a rete intercalated in the course of the internal carotid 
artery 

The internal carotid artery leaves the cavern 
ous sinus by perforating the dura mater It 
immediately gives off a caudal branch, the 
caudal communicating artery The mam 
stump of the internal carotid artery continues 
rostrad on the ventral surface of the optic 
tract, where it forms a curvature to course m a 
medial direction During tills course it comes 
to he on the dorsal aspect of the optic chiasma 
and optic nerve Here, it divides into two sets 
of branches the middle cerebral artery and 
rostral cerebral artery,* the latter may be re 
garded as the continuation of the parental ar 
tery During its course, and before the above 
branches are formed, the internal carotid ar- 
tery gives off a number of branches as fol 
lows 

The internal carotid artery gives off two or 
three branches the rostral (superior) hjpo- 


•Also termed the nasal 1 ranch or nasal communicating 
artery 







U-PORCINE HEART ANI> ARTERIES 


1317 


physial arteries, which course medially to 
distribute on the tuber cinereum, optic clii 
asma, and around the proximal part of the 
neurohypophysis (infundibulum) These 
branches join with the branches of the contra- 
lateral side as well as with the medial branches 
from the caudal communicating arter> to 
participate in the blood supply to the hypo- 
thalamic floor, optic chiasma, pars inter- 
media, infundibulum, and, indirectly, to the 
pars distalis 

The internal ophthalmic artery leaves the 
internal carotid artery as a very fine vessel 
This vessel courses on the ventral surface of 
the optic chiasma and optic nerve ventrolat 
eraliy It winds around to come on the dorsal 
aspect of the optic nerve It leaves the cranial 
cavity through the optic foramen to enter the 
orbital fossa and joins the anastomotic branch 
from the external ophthalmic artei y (ciliary 
artery - Prince, et al 1 960) 

The rostral choroidal artery takes its origin 
from the internal carotid arteiy It leaves the 
above artery ventrolaterally and courses along 
the optic tract under covei of the piriform lobe 
and parahippocampal gyrus It enters the lat 
eral ventricle, where it terminates by giving 
branches to the tela choioidca for the choroid 
plexuses of the lateral and third ventricles It 
supplies branches to the piriform lobe optic 
tract, lateral geniculate body, cerebral crura, 
and other associated structures in its course 
Aj the Xeie) of j)m* X stem) (temeoiote bad} tXte 
artery receives a communicating branch from 
the caudal choroidal artery a branch of the 
caudal cerebral artery 

The manner of origin of the middle cerebral 
artery is different in the pig than in cattle 
sheep, goat, horse, dog, and cat The artery 
generally docs not have a single common stem 
of origin as is seen in the above mentioned 
animals, but in the pig two to three branches 
arise from the internal carotid artery in close 
proximity These branches may be collectively 
termed the middle cerebral arteries I low cv cr, 
from a comparativ c point of v jew , these repre- 
sent the brandies of the middle cerebral artery 
of other domestic animals These branches 
course dorsolatcrally rostral to the pinform 
lobe and \ cntral aspect of the rostral perforate 
Mibstancc to reach the 1 iteral rhinal sulcus 
and distribute on the lateral, dorsolateral, and 


rostrolateral parts of the cerebral hemisphere 
The branches of the middle Cerebral arterv, on 
reaching the lateral rhinal sulcus, again di- 
vide into a number of branches in a vanable 
pattern and distribute over the lateral surface 
of the cerebral hemisphere, except rostro 
laterally, where they s e nd perforating 
branches to the cortices of the different areas 
including the piriform lobs and insula The 
branches of the middle cer e bral artery, dur- 
ing their initial course, before reaching the 
lateral olfactory tract (stria), give off a number 
of perforating branches These branches 
enter through the rostral pe r f or ate substance 
and the rostral part of the pinform lobe to 
supply the caudate nucleus, amygdaloid body, 
pallidum, putamen, and internal capsule 
laterally They may send a f ew blanches 
which supply the external capsule and 
claustrum The brandies may be termed the 
central branches (lateral st^ a t e branches) 

The rostral cerebral artery 1S the direct con 
tinuation of the internal carotid aitery The 
artery runs rostrally in the m e dian plane along 
the ventral aspect of the medial olfactory tract 
and longitudinal fissure 

The rostral communicating artery m the pig 
is represented by a reticulated or plexiform 
network formed at the level 0 f the origin of 
the rostral cerebral artery The network is 
contributed to by one or t\\ 0 fine branches 
from the rostral cerebral arte nes of both sides 
Some fme branches may jjJs# come from the 
internal carotid artery at the* level of its divi- 
sion into the middle and rofct ra i cerebral ar- 
teries 

The rostral cerebral arte ry> while in its 
course along the ventral surf acc of tlie medial 
olfactory tract, reaches near the caudal end of 
the olfactory' bulb Here it bo n ds to ascend on 
the medial surface of the ccn»bml hennsnhorr 
for a very’ short distance and joins with the 
similar contralateral artery The fused art enal 
trunk is termed the ^common (median) nrterv 
of the corpus callosum because of the complete 
fusion of the arteries of both sides and their 
subsequent common course Tins artery 
courses dorsad in the interlKj m!S phenc space 
and curves cuudad to reach the genu of the 
corpus callosum, thereafter U continues cau- 
dally on the dorsal aspect of ( hc corpus caflo 
sum In its course it gives off tortical branches 



POKCINE 


1318 

for the cerebral gyn approximately on the 
cramal half of the medial surface of both cere 
bral hemispheres Its branches are also dis 
tributed to the dorsal aspect of the cerebral 
hemispheres The artery terminates by anas 
tomosing with the cortical branches of the 
caudal and middle cerebral arteries 
The internal ethmoidal artery is the rostral 
continuation of the rostral cerebral artery 
after the common (median) artery of the cor 
pus callosum is given off The internal eth 
moidal artery continues rostrad along the 
medial olfactory tract reaches the rostral part 
of the olfactory bulbs and perforates the dura 
mater to reach the lamina cribrosa where it 
forms a rete along with the branches of the 
external ethmoidal artery The internal eth 
moidal artery during its course gives off 
branches to the olfactory bulb and anasto- 
moses with the artery of the opposite side The 
olfactory branches may come from the rostra! 
cerebral artery 

As already indicated the cortical branches 
are given off by the common (median) artery 
of the corpus callosum in the interhemisphenc 
space to distribute on the medial surface of 
each cerebral hemisphere In addition to 
these two or three large cortical branches are 
given off by the rostral cerebral artery itself 
while it courses along the medial olfactory 
tract in the median plane These branches 
course laterally on the ventral surface of the 
olfactory tngone and ascend on the lateral ol 
factory tract to cross the lateral rhinal fissure 
and divide to distribute on the cranial or fron 
tal pole of the cerebral hemisphere 
The central branches are fine branches given 
off by the cortical branches of the rostral 
cerebral artery during their course on the ven 
tral aspect of the olfactory trigone These 
penetrate the above area and Bupply the ros 
tral and rostromedial parts of the caudate 
nucleus putamen pallidum and internal 
capsule and may be termed the central 
branches (medial striate branches) 

The caudal communicating artery is the cau 
dal branch of the internal carotid artery It ex 
tends between the internal carotid artery and 
the basilar artery and is divided into two seg 
ments the proximal corresponding to the 
proximal part of the caudal cerebral artery 
and the distal corresponding to the mesen 
cephalic artery of Kaplan (1956) in the human 
in view of the topography and neurovascular 
relationships It gives off the caudal cerebral 
artery rostral to the origin of the oculomotor 
nerve The ^mesencephalic artery (or the dis 
tal segment of the caudal communicating ar 
tery) was referred to as the terminal part of 
the basilar artery by Jenke (1919) The proxi 
mal part of the caudal communicating artery 
is related dorsally to the cerebral crura. It 
gives off a number of small medial and lateral 


branches in its course to supply the hypothal 
amus subthalamus hypophysis and cerebral 
crura. 

The caudal cerebral artery is regarded ns 
one of the branches of the caudal communi 
eating artery The artery curves dorsolaterally 
to ascend along the cerebral crus and comes 
under the caudal part of the piriform lobe It 
crosses the medial geniculate body to come 
in relation with the parahippocampal gyrus 
In its further course It is related to the pulvinar 
and lateral geniculate body vcntrally The 
terminal part of the artery leaves the associa 
tion of the parahippocampal gyrus at the sple 
nium of the corpus callosum and distributes 
in the caudal and caudomedial part of the 
cerebral hemisphere It joins with the ter 
minal portion of the rostra! cerebral artery 
During Its initial course the caudal cerebral 
artery gives off a number of branches to the 
cerebral crus optic tract medial geniculate 
body and parahippocampal gyrus In addition 
to the above the following branches are given 
off in its course 

A number of cortical branches are given off 
by the caudal cerebral artery throughout its 
course While in association with the hippo- 
campus a number of cortical branches are 
given off for distribution on the caudal pole or 
occipital pole of the cerebral hemisphere In 
eluding the caudal part of the piriform lobe. 
(As already indicated a number of cortical 
branches arc given off after the caudal cere 
bral artery comes on the caudal and caudome 
dial aspect of the cerebral hemisphere These 
cortical branches anastomose with the cortical 
branches of the middle and rostral cerebral 
arteries in the interhemisphenc space ) The 
caudal cerebral artery itself terminates on the 
dorsal aspect of the corpus callosum where it 
joins with the terminal branch of the rostral 
cerebral artery (common [median] artery of 
the corpus callosum) 

The caudal cerebral artery gives off two or 
three branches at the level of the lateral ge 
niculate body and pulvinar These branches 
course medially to supply the dorsal thalamic 
areas pulvinar lateral geniculate body and 
pineal body and contribute branches for the 
supply of the choroid plexuses of the lateral 
and third ventricles by anastomosing with the 
caudal choroidal artery given off by the 
^mesencephalic artery 
The caudal communicating artery after 
releasing the caudal cerebral artery continues 
caudad as the mesencephalic artery It 
courses caudally on the ventral surface of the 
cerebral crura and meets with its fellow of the 
opposite side near the rostroventral border of 
the pons and ventral to the caudal perforate 
substance and joins the basilar artery It gives 
off a number of branches during its course 
The caudal choroidal branch is given off 



44 — PORCINE HEART AND ARTERIES 


1319 


from the mesencephalic artery, general!} in 
common with the branch to the rostral mesen 
cephalic tectum It courses dorsolaterally to 
reach rostral to the rostral colliculus tv here 
it takesarostromedial course and supplies the 
choroid plexus of the third ventricle pineal 
body, and associated structures It also anas 
tomoses with branches of the caudal cerebral 
artery and the branch to the rostral mesence 
phahc tectum 

The <J>braneh to the rostral mesencephalic 
tectum anses from the mesencephalic artery 
and courses around the cerebral crus b) dn id 
ing into tvv o or three branches These branches 
come on the dorsal aspect oi the rostral col 
liculus and groove between the two colliculi 
It anastomoses with the caudal branch of the 
same name, branch of the contralateral side 
and caudal choroidal artery The binnch sup 
plies branches to the cerebral crus tegmen 
turn and rostral colliculus It may also send 
branches to supply the pineal body and associ 
ated structures 

The odorsomedial branches (posteromedial) 
are line branches given off by the terminal 
portion of the mesencephalic artery and its 
union with the contralateral artery to join the 
basilar artery The number of \ essels is \ an 
able The branches are directed dorsomedially 
to perforate the caudal perforate substance 
mamillary body, and cerebral crus These 
branches supply the mesencephalic areas 
located in the median plane such as the inter 
crural nuclei, substantia mqra nucleus ru 
brum and associated fiber tracts and nerve 
mots Among these branches two are larger 
than the rest and supply the subtlialamus and 
caudal thalamic areas, and are termed the 
thalarnoperforating artenes in the human by 
some authors 

The rostral cerebellar artery leaves the cau 
cat communicating artery near its terxnma 
tion and union with the basilar artery and 
courses dorsolaterally It crosses the cerebral 
crus and comes in the space between the cere 
bellum and caudal colliculus, where it gives 
off its terminal branches The rostral cercbel 
vtr artery gives off a number of perforating 
branches in its course, these supply the reticu 
w formation, caudal colliculus, cerebral crus 
orachium of the pons and trigeminal nerve 
the artery terminates by giving ofT three ter 
nthnl branches— lateral intermediate and 
medial— for distribution on the rostral and 
uorvv! parts or the cerebellar hemisphere and 
tcrmts ctrtbcffi ol its own side These 
“ r \ ,lc hes intemnastomose with each other 
ond with the branches of rite caudal cerebel 

ar artery , one or tw o accessory rostral cerebcl 

•V arteries may be present in some c ises 

ibe unrr? K varul l< tuch that It mu irt«at 
«*** ° f Rw**cnc« pbabe anertesur -uvmm< tfirally 
*iC«t srtrry arivrt fttim tl c mrvewei luhc artery and 


the left arises from the union of the meseotephahcarteries 
In i very few eases the rostnl certbellai utery miy come 
off unihterally Irom the bisihi irltrj In view of the fre- 
quency uid pattern of llie orij,m the rostral cerehrihraritry 
is rcpaided is i branch of the mesencephalic artery ft is 
substantiated In the fitt that the b isilui trtery m thepon 
tine rceion is of stmllci e dibcr than eithei the rostral cere 
In Harm inesenccphihcaitciv 

The i/»bi«nch to the caudal mesencephalic 
tectum is given off from the lostral cerebel 
lai artery It courses rostrally over the caudal 
colliculus dorsolaterally and perforates the 
tectum It anastomoses with the branch to the 
rostral mesencephalic tectum and the contra 
lateral caudal branch It supplies the caudal 
colliculus and associated structures The cau 
dal colliculus also leceivesafewfine blanches 
from the terminal medial branch of the rostral 
cerebellar artery 

The foi mation of the hasilar arten has been described by 
Becker I9G0) According to him the occipital arteiy gives 
oil the descending branch in the alar fossa which passes 
through the transverse c inal of the atlas anastomoses with 
the vertebral artery and enters the vertebral canal at the 
level of the atlas It courses in n tortuous manner on the 
Literal wall and runs rostrally It gives off fine twigs to the 
meninges The occipital branch which is the terminal 
branch of the occipital artery passes through the lateral 
vertebral foramen oi the atlas to continue as the cerebro- 
spinal artery The descending branch of the occipital artery 
joins the occipital branch at the lateral vertebral foramen 
The cerebrospinal artery after i ntering the vertebral canal 
forms a small triangular rete mirabile The cerebrospinal 
artery divides into the basilar and ventral spinal branches, 
which join with similar branches from the opposite side to 
form the basilar artery rostrally and ventral spina! artery 
caudally on the ventral surface The basilar branch receives 
the vertebral artery at the foramen magnum 

However according to N A V (1968), the 
basilar artery may be regarded as a branch of 
the vertebral artery This is based on the fact 
that the descending branch and berebrospmal 
artery of the pig correspond to the terminal 
parts of the vertebral artery of man Accord 
ing to the above the vertebral artery ascends 
in the neck through the transverse foramina 
and reaches the atlantal fossa The vertebral 
artery anastomoses here with the occipital 
artery through an anastomotic branch with 
the occipital artery and the descending branch 
pnd passes through the alar foramen and 
lateral vertebral foramen into the vertebral 
canal The artery courses on the lateral wall 
of the vertebral canal at the level of the atlas 
in a tortuous manner and joins to form the 
caudal epidural rete mirabile with the con 
d>Hr artery and spinal branch The artery 
continues rostrad to join with the vertebral 
arten of the opposite side to form the basilar 
arten 

The caudal epidural rete mirabile is present 
in the pig and is formed b> the branches of the 
oecipit il and vertebral nrtenes The rite is 
comparative!} smaller in the pig than in cat 
tie It is formed at the level of theatl is and axis 
vertebrae and continues rostrally for a short 



I ORCINF 


1320 

distance The rete does not communicate with 
the rostral rete as it does in cattlt The oc 
cipital artery Rives off a branch the condvlir 
artery which passes through the hypogloss il 
foramen and joins with the branches of the 
vertebral artery and spina! branch to complete 
the rete formation 

The basilar artery continues rostrallv on the 
central aspect of the medulla oblonu.ua 
trapezoid bod> md pons inaflexuous manner 
The diameter of the basilar arteiy narrows as 
it courses rostrally This is noticeable in its 
pontine segment where it igain increases in 
caliber by joining the internal carotid blood 
source The basilar artery m its course Rives 
off a number of branches 
The <J>paraim dian branches are fine branches 
Riven off from the dorsomcdial aspect of the 
basilar arter) throughout its course These 
branches perforate the medulla oblongata 
trapezoid bodv and pons ventromedially 
through the v entral medi in Assure and basilar 
sulcus to supply the nuclear fields and tracts 
in the median plane of the above mentioned 
segments of the brain 

The basilar arter} m Us initial course giv es 
off three to four ^medullarv branches These 
branches course dorsohterally come under 
cover of the accessor} nerve and bend medt 
ally on the dorsal surface of the medulla 
oblongata These branches anastomose with 
each other during their course The} giv c per 
fonting branches to the medulla oblongata 
The basilar artery continues rostrad after 
giv ing the preceding branches It reaches ap 
proximately the origin of the abducent nerve 
where it gives off the caudal cerebellar artery 
During this course between the origin of the 
preceding branches and the caudal cerebellar 
arter) the basilar artery giv es off a few small 
collateral branches which supply the medulla 
oblongata by sending perforating branches 
The caudal cerebellar artery courses dorsolat 
erall> and obliquely It reaches the dorsal as 
pect of the medulla oblongata by curving 
medially rostral to the glossopharyngeal 
nerve It comes in relation with the cerebellar 
hemisphere and the choroid plexus of the 
fourth ventnelo and terminates by dividing 
into three cerebellar branches -lateral inter 
mediate and medial During the course of the 
caudal cerebellar artery both ventrolateral 
and dorsal to the trapezoid body and medulla 
oblongata it sends a number of perforating 
branches into the substance of the above 
mentioned structures In addition to the 
above it gives off branches for the choroid 
plexus of the fourth ventricle The caudal 
cerebellar artery during its course anasto- 
moses with the adjoining collateral branches 


The caudal cerebellar artery during its course 
along the nerv e roots of the faci U and \ cstibu 
locochlcar nerves gives of! i small branch 
which courses between the above mentioned 
nerve roots and ascends to curve on thedorso 
literal ispect of th* pons to distribute on the 
ventrolateral pirts of the floccuhr and para 
floceular lobes It an istomoses with the 
branches of the rostral and caudal cerebellar 
irtenes It is alsojaint-d b> one or two branches 
to the pons rostral to the facial nerve The 
ibove artery m iy be termed the middle cere 
hellar irtery 

The labyrinthine artir) is a halrhke vessel 
which takes its origin from the middle Ct rc 
bcllar artery md enters the internal icousttc 
meatus to distribute m the internal ear 

nicre are three to four branches to the pons 
given ofTby the basilar artery These collateral 
branches arc distributed over the ventral and 
dorsolateral parts of the pons and the tngemi 
nal nerve They supply perforating branches 
»o the pons and anastomose with branches of 
the caudal and rostral cerebellar arteries 
The occipital arterv (Tig 44 5) usually 
arises by a common trunk with the internal 
carotid or from the common carotid as a 
terminal branch It anastomoses with the 
vertebral artery in the atlantal fossa It Rives 
ofr the occipital branch supplying the stemo 
mastoidcus longus capitis rectus capitis 
ventralis rectus capitis lateralis and some 
limes the splenius cervicis At the level of 
the wing of the atlas it releases the caudal 
meningeal arterv which after supplying the 
flexors of the he id enters the cranial cavity 
via the temporal canal and ramifies in the 
dura mater According to Becker (1960) it 
arises In exceptional cases from the condylar 
artery 

by N G Ghosh al 
THORACIC IIMB 

The axillary arter) is the continuation of the 
subclavian after the origin of the superficial 
cervical artery on the left side (on the nght 
side the latter artery arises from the thyrocer 
vical trunk) A true superficial cervical ar 
tery is frequently absent as both the ascending 
and prescapular branches usually arise inde 
pendently from the subclavian artery Some 
times the prescapular branch tomes from the 
external thoracic artery- The axillary artery 
after vvindmg around the cranial border of the 
first nb courses caudoventrally to the inter 
val between the subscapulans and teres 
major muscles where u divides into (1) a 
common trunk for the subscapular and thora 
codorsal artenes (2) a common trunk for the 



4 1 -PORCINE HEART AND ARTERIES 


1321 


suprascapular, cranial circumflex humeral, 
and caudal circumflex humeral arteries, and 
(3) the brachial artery Sometimes the supra 
scapular artery arises from the subscapular on 
the flexor surface of the shoulder joint The 
chief branches or the axillary artery are as 
follows 

1 The external thoracic artery main!) sup- 
plies the pectoral and bmchioceplnhcus It 
detaches the lateral thoracic artery accompa 
nywg the corresponding nerve on the lateral 
thoracic wall Dunng its course the latter 
artery furnishes variably the mammary 
branches to the first two pairs of thoracic 
mammae Occasionally, the prescapular 
branch of the superficial cervical artery 
arises from it (Fig 44-10) 

2 The subscnpulnr artery arises together 
Nith the thoracodorsal and courses dorsocau 
dally along the caudal border of the scapula 
between the subscapulans and teres major 
(Ftg 44-7) It gives muscular branches to the 
triceps brachii (long head), infraspinatus, 
rhomboideus, supraspinatus, dcltoidcus 
teres minor, teres major, latissimus dorsi, and 

subscapularis 

The circumflex scapular artery separates 
from the subscapular near the middle of the 
caudal border of the scapula It passes be 
tween the subscapulans and the long bead of 
the triceps brachii, and is distnbuted in the 
latter muscle The nutrient artery of the scap 
ula usually anses from this vessel 

3 The thoracodorsal artery anses together 
w ith the subscapular as one termination of the 
axillary artery (Fig 44-7) It continues caudo 
oorsally over the medial surfaces of the teres 
major and latissimus dorsi and is expended 
y^thm the interstices of the latter muscle 
tJunng its course it gives collaterals to the 
Preceding muscles, pectoralis ascendens, 
scalenus dorsalis, and serratus ventrahs 

n ora cis and, after piercing the latissimus 
aorsi > the cutaneus trunci and the skin cov- 
ing the same 

4 The caudal circumflex humeral artery 
passes laterally between the teres major and 
!}! bS ^ pu,aris alon S t * ie caudal aspect of the 
fhj Gr ^ 01nt 1* emerges on the deep face of 
me deltoideus, where it divides into two 
Branches (Fig 44-7) Merz (1911) describes 
n,S Tif se * as ansin S from the axillary artery 

a , , e Proximal branch passes along the 
auaolateral aspect of the shoulder joint, by 
» p ® ate< l branching it furnishes the longhead 
Jr* e tnc eps brachu deltoideus, teres minor, 
raspmatus, braehiahs and subscapulans 
sboultter cram °l atera l aspect of the 

branch (collateral radial artery) 
nunues the parent vessel distocaudally be 


tween the braehiahs and the long head of the 
triceps brachii, accompany mg the radial nerve 
in the musculospiral groove (mtcus m 
braehiahs) of the humerus On the flexor sur- 
face of the elbow joint it anastomoses with a 
branch of the transv erse cubital artery During 
its course it releases muscular branches for 
the tnceps brachii, braehiahs, anconeus, and 
extensor carpi radialis muscles and the lateral 
and caudolateral aspects of the elbow joint • 
As a rule the nutnent artery' of the humerus 
arises from the collateral radial artery 

5 The suprascapular artery is usually large 
and has a vanablc ongin (Fig 44-7) It passes 
dorsocranially between the subscapulans and 
the costal surface of the scapula Slightly 
dorsal to the supraglcnoid tubercle it divides 
into three branches, supplying the subscap- 
ulans.supraspmatusand pectoralisascendens 
and the cramomcdial aspect of the shoulder 
joint It continues further laterad, between the 
subscapulans and supraspinatus, accompany- 
ing the homonymous nerve and ramifying in 
the latter muscle 

6 The cranial circumflex humeral artery has 
an extremely vannble ongin (Fig 44-7) It 
may anse from the caudal circumflex humeral 
artery, brachial artery or from the subscapular 
trunk (Badawi, 1959) It is a relatively large 
vessel, passing distocraniad between the two 
parts of the coracobrachialis It gives branches 
to the preceding muscle, the pectoralis as 
eendens supraspinatus, biceps brachii, sub 
scapulans, teres major, and the cranial, medi- 
al and caudomedial aspects of the shoulder 
joint 

The brachial artery is the other terminal 
branch of the axillary and continues in the 
arm, accompanying the median nerve (Fig 
44-7) It lies at first between the coraco 
braehiahs and the medial head of the tnceps 
brachii, and then between the biceps brachii 
and the flexor surface of the elbow joint, be 
neath the pectoralis descendens and pronator 
teres Distal to the elbow joint it gives off the 
common interosseous artery and continues 
further as the median Dunng its course it 
detaches muscular branches for the coraco 
braehiahs, pectorahs ascendens, pronator 
teres, flexor carpi radiahs, and the flexor digi 
torum superficialis The chief branches of the 
brachial artery are 

1 The deep brachial artery is usually of 
considerable size, but it maybe represented by 
small vessels, however, according to Merz 
(1911), it is apparently absent and its area of 


•According to N A V (1968) in Artlodactyfa the ennfal 
superficial antebrachial artery originates from the collateral 
radial artery from which the dorsal common digital artery 
III and the dorsal proper digital arteries anse 



1322 


■OKCIM 



Hf.Utt II-" \rtcrial Mood xupplv to thoracic 
hmh of domestic pic »«* axillary artery, media! 
xiew, schematic 

4 AxiUarx a < subscapular a 6 suprascapular# 7 
prt ximsl branch of « .md.il circum'fex humeral a " dts 
tal branch to Liura! radial) of caudal circumFex humeral 
a 8 continuation of 6 8 circumflex scapular a. 9 
thoracodorsal a 10 bnichial a 11 cranial circumflex 
humeral a 12 deep brachial a 13 colla eral ulnar a. 15 
Iransxerse cubital a IS proximal branch (bicipital a) 
la dual branch IG common interosseous a. 17 caudal 
interosseous a. 1 ~ dorsal t interosseous) branch 17* pa! 
mar braruh 18 rranul Interosseous a 18 recurrent in 
terosseousa 10 median a 20 ndata 20 dorsal carpal 
brand es of radial a 2S dorsal tomiw-n digital a. 11 *»G 
dorsal proper digital aa 1J and III (From Chosh.iI and 
Celts I9G8 * 



44 —PORCINE HEART AM) ARTERIES 


1323 


supply is taken over by the collateral radial 
artery It courses eaudally and mainly vascu 
lanzes the tnceps braclm 

2 Near the middle of the arm a large mus 
cular branch arises from the parent vessel 
which, after vascularizing the medial head of 
the tnceps brachii, enters the biceps brachii 

3 The collateral ulnar arterj lea\cs the 
brachial slightly proximal to the olecranon 
Following a short course it gives off small 
branches for the medial head of the triceps 
brachii, tensor fasciae antebrachn, humeral 
and ulnar heads of the flexor digitorum pro 
fundus, pectorahs transversus, the caudo 
medial aspect of the elbow joint and the 
fascia and skin on the caudal aspect of the 
forearm to the carpus A long, slender branch 
(ramus carpetts palmaris) continues chstally. 


accompanying the ulnar nerve in the groov e 
between the flexor carpi ulnans and the 
flexor digitorum profundus Slightly proximal 
to the accessory carpal bone it anastomoses 
with the superficial palmar branch of the 
caudal interosseous artery 
4 The transverse cubital (former distal col 
lateral radial) artery arises from the brachial 
on the flexor surface of the elbow joint Deep 
to the biceps brachii and brachialis it divides 
into a proximal and distal branch It gives col 
laterals to the preceding muscles brachio 
cephalic us pectoralis transversus, and the 
Cran ~, as P ect of the elbow joint 
a The proximal branch (bicipital a ) after 
oursmg between the brachialis and the ex 
ensor carpi radialis, anastomoses with the 
y! aten fl radial arterj as indicated above In 
, ition 11 releases small twigs to the ad 
joining muscles 

branch is large and anastomoses 
" tiie recurrent interosseous artery of the 
nial interosseous It detaches branches for 
ie extensor carpi radialis and the extensor 
“‘forum communis 

deep antebrachial arterj anses from 
mint C .i ^ Im mediately distal to the elbow 
1*. 1 dn A supplies the muscles of the caudal 

G e T1? Fthef0reai ' m 

i_ . , ‘o 6 common interosseous arterj is the 
Q i> , ra nch of the brachial, arising at the level 
,, prox,ma l Part of the (proximal) interos 
fniinf , s fl a , ce °f the forearm It gives off the 
branches (Fig 44-7) 

iu‘. T* 1 ? cau da1 interosseous arterj assumes 
CQ ‘ sta * ^tension of the parent vessel It 
mucs tnside the interosseous space of the 
i rin 3 ™? ani * at di st al third, divides into 
oss erf? 1 \\ nt * h'dmar branch The dorsal (inter 
die ,»m branch CQ «ras deep to the abductor 
tn |t“ 1 lon Bus and emerges slightly proximal 
I,.,, j carpus On the dorsal aspect of the car 
nkrt twigs to the joint capsule and 

nal ** ie f° rm ation of the dorsal car 

c Hie palmnr branch soon divides into 


superficial and deep branches The former 
furnishes twigs to the palmarolateral aspect 
of the carpus, the ulnans lateralis and the 
flexor digitorum superficialis After coursing 
deep to the ulnans lateralis it anastomoses 
with the collateral ulnar artery slightly proxi 
mai to the accessor) carpal bone Distal to the 
carpus it releases an anastomotic branch to 
constitute the (proximal) deep palmai arch 
and gives off the dorsal common digital artery 
IV (in the absence of the corresponding dorsal 
metacarpal artery) The latter vessel passes 
through the fourth mtermetacarpal space and 
appears on the dorsal aspect of the manus and 
near the fetlock joint, divides into dorsal 
proper digital arteries IV and V, descending 
along the abaxial surface of the fourth and 
axial surface of the fifth digits The superficial 
palmar branch releases a communicating 
branch to palmar common digital artery IV 
Its deep branch supplies the palmar aspect of 
the carpus 

b The cranial interosseous arterj is slender 
and after coursing over the abductor digiti I 
longus it contnbutes to the dorsal carpal rete 
During its course it gives off the recurrent 
interosseous arterj ai the level of the proximal 
part of the (proximal) interosseous space of 
the forearm The latter vessel passes disto 
craniad and furnishes the extensor digitorum 
lateralis extensor digitorum communis and 
abductor digiti I longus It extends deep to the 
preceding muscles and anastomoses with the 
transverse cubital artery 

The median arterj is the distal extension of 
the brachial beyond the origin of the common 
interosseous It descends along the caudome 
dial aspect of the radius beneath the pronator 
teres and flexor carpi radialis muscles and 
continues further through the carpal canal 
beneath the flexor retmaculmn Here, it gives 
off a slender branch which after describing 
an arch around the tendon of insertion of the 
flexor carpi radialis joins the radial artery 
Near the middle of the metacarpus the con 
Unuation (lateral or ulnar branch) of the 
radial artery anastomoses with it, thus con- 
stituting the superficial palmar arch, beyond 
which it continues as palmar common digital 
artery III It gives muscular branches to the 
flexor digitorum superficialis The chief col 
lateral branches of the median arterj are 

The radial arterj anses from the median 
near the middle of the forearm and descends 
between the caudomedial aspect of theradius 
and the flexor carpi radialis and continues 
along the palmaromedial aspect of the carpus 
(Figs 4 4-7 and 8) Slightly distal to the base 
of the second metacarpal bone it gives off the 
deep branch, near the middle of the second 
metacarp il bone the radial artery divides into 
a lateral and a medial branch The lateral (ul- 
nar) branch joins the median to form the 



J324 



racic limb of domestic pig palmar new schematic 
13 Distal continuation of col Lai era] ulnar a 17" palmar 
branch of caudal interosseous a 19 median a. 20 radial 
a. 20 dorsal carpal branch of radial a 21 deep branch of 
20 22, superficial palmar arch 24 common palmar d gi 
tala. 11 25 palmar proper d g tal aa 11 and III 26 palmar 
common digital a. Ill 29 proximal perforating branch 
31 dorsal branch of middle phalanx 35 palmar meiacar 
pal a IV 36 (proximal) deep palmar arch 37 (d stal) 
deep palmar arch 38 branch to bulbar reg on 39 palmar 
branch of d stal phalanx 40 palmar common d gltal a IV 
41 palmar proper d gltal aa IV and V 42 dorsal common 
digital a. IV 43 palmar proper d gital aa Ilf and IV 43 
palmar branches of proximal phalanx 44 palmar meta 
carpal a. Ill 45 palmar metacarpal a. II 50 medial (abax 
lal) palmar digital a. 11 (From Gboshal and Getty 1 968 > 


superficial palmar arch The medial branch 
after giving off a communicating branch to 
palmar common digital artery II close to the 
latter s origin descends as the medial (abaxi 
al) palmar digital artery along the abaxial side 
of the second (media! accessory) digit The 
chief branches of the radial artery are 
a The branches to the dorsal carpal rete 
anse variably quite apart from each other 
usually one proximal and the other distal to 
the level of the carpus The dorsal metacarpal 
arteries anse vanably from this vascular net 
work In fact dorsal metacarpal artenes II III 
and IV may anse from the latter or from the 
corresponding palmar metacarpal artenes (in 
the absence of the corresponding dorsal ves 
sels) However dorsal metacarpal artery III 
usually descends from the dorsal carpal rete 
and is connected with the (proximal and dis 
tal) deep palmar arches by means of corre 
sponding perforating branches (Fig 44-9) 
Following the anastomosis of the distal per 
forating branch dorsal metacarpal artery III 
descends as dorsal common digital artery III 
which near the middle of the proximal 
phalanx gives off axial dorsal proper digital 
artenes III and IV and by traversing the inter 
digital space it empties into palmar common 
digital artery III thus forming the mterdigital 
artery * 

b The deep branch separates from the radial 
artery slightly distal to the base of the second 
metacarpal bone Following a short course it 
detaches an anastomotic branch which after 
coursing laterad between the mterossei mus 
cles and metacarpal bones joins a similar 
branch from the superficial palmar branch of 
the caudal interosseous artery thereby con 
stitutmg the (proximal) deep palmar arch 
Small twigs from the arch supply the Inter 
ossei muscles and the caudal aspect of the 
carpus Palmar metacarpal artery III con 
tinues distally from this arch and joins palmar 
metacarpal artenes II and IV forming the 
(distal) deep palmar arch From the latter 
arises the distal perforating branch which 
after traversing the third intermetacarpal 
space anastomoses with the corresponding 
dorsal metacarpal artery slightly proximal to 
the fetlock joint Later the deep branch divides 
into dorsal common digital artery II and pal 
mar metacarpal artery II although the latter 
vessel may anse from the superficial palmar 
branch of the radial Dunng its course it 
furnishes the flexors adductors and abductors 
of the second digit Dorsal common digital 
artery II (in the absence of the corresponding 
dorsal metacarpal artery) after passing 
through the second Intermetacarpal space re 


‘Accord ng toN A.V (1968) the crania! *uperfcial ante- 
brachial artery of the collateral radial g ve* off dorsal com- 
mon dig tal artery III 



44-PORCINE HEART AND ARTERIES 


1325 



u-s 


^ nr 

Tkt{ * wf <l,Rla l P ar * rijrht th<v 

^ ^ domentir p,R. ,l nnnl ^ bpmiltlf 

c* ** * *«»Ul hrirnni™!'* ,,r "»ncli or ciuiUI intcrtmcoie 
^rr* * r * ‘ l) , l!f ' TV1 ’ t»Uw! bnnrh*** 

**V*^wh M ^ Wrucaipat , Itl -12 di»u' 
**v av-n rf 111 A«id IV 

***’*'’4 1 % 4 (> . * « a l\ 11 jMlnur pmpi*T dlu» i! 

" ■■«*"' <» 


leases a few branches to the dorsal carpal rete 
and, near the fetlock joint divides into dorsal 
proper digital arteries II and III descending 
along the axial surface of the second and 
abaxial surface of the third digits, respective- 
ly (Fig 44-9) 

Palmar common digital artery III is the 
distal extension of the median beyond the 
superficial palmar arch (Fig 44-8) While 
coursing along the palmar aspect of the fet- 
lock joint it receives the anastomotic branch 
from the (distal) deep palmar arch and, near 
the middle of the proximal phalanx, it divides 
into palmar proper digital arteries III and IV, 
coursing along the axial surfaces of the third 
and fourth digits At this site of the respective 
digit the axial (sometimes the interdigital) 
artery gives off the proximal phalangeal arterj 
which soon divides into dorsal and palmar 
branches of the proximal phalanx Each of the 
latter branches extends deep to the flexor ten 
dons along the palmar suiface of the proximal 
phalanx and joins the palmar proper digital 
artery on the abaxial surfaces of the third and 
fourth digits, respectively Following the 
anastomosis it continues dorsad and gives a 
reinforcing branch to the dorsal proper digital 
artery coursing along the abaxial surfaces of 
the third and fourth digits, respective!) In 
addition palmar proper digital artcnes III 
and IV are connected with dorsal common 
digital artery 111 by means of the mtcrdigital 
artery, as indicated previously Both the pal- 
mar proper digital artencs finally divide into 
three branches ->a strong branch supplies the 
subcutaneous cushion and the conum of the 
bulbar region ( ramus tan digitalis) and the 
other two supply the palmar surface and the 
conum of the distal phalanx The palmar 
proper digital artencs, slightly proximal to the 
distal sesamoid, detach the dorsal branch of 
the middle phalanx forming the coronary ar- 
tenal circle After entering the distal phalanx 
they form the terminal nrcli. The dorsal branch 
passes dorsad along the medial surface of the 
middle phalanx and furnishes the fascia and 
skin of the adjoining area Opposite the origin 
of each dorsal branch of the middle phalanx 
arises a very slender palmar branch of the 
middle phalanx which connects (axial and 
abaxial) palmar digital orient s III and JV On 
its course palm ir common digital artery III 
gives ofT 

1 Palmar common digital artery II anses 
from the parent vessel on the palmar «*|H.ct 
of the fetlock joint, where it receives n com 
munlcating branch from the superficial pal 
mar branch of the ndial It tin hits into palmar 
proper digit il entries II and III, dttcemlim; 
on the axi il surface of the second and nhaxiai 
surface of the third digits respectively 
Palmar (abaxial) proper dii.it il anirv III I* 
connected with the corn * ponding axul ves 



I ORCINE 


1326 

s«*l of the third digit % la the palmar branch of 
the proximal phalanx near its middle 
2 Palmar common digital artery IN arises 
from the parent vessel slightly distal to the 
preceding artery on the palmar surface of the 
fetlock joint where it anastomoses with a 
communicating branch of the superficial 
palmar branch of the caudal interosseous ar 
tery Later it divides into palmar proper digi 
tal arteries IV and V extending along the 
abaxial surface of the fourth and axial surface 
of the fifth digits respectively Palmar 
(abaxial) proper digital artery IV is connected 
with the corresponding axial vessel of the 
fourth digit by means of the palmar branch of 
the proximal phalanx similar to that of the 
third digit 


Descending Aorta 


THORACIC AORTA 

The bronchial and esophageal branches of 
the bronchoesophageal artery frequently 
anse separately from the thoracic aorta The 
bronchial branch passes ventral to the tra 
cheal bifurcation and divides into four 
branches which (together with the bronchial 
veins) form its own capillary bed (Zietz 
schmann etal 1943) The esophageal branch 
is usually represented by two vessels supply 
ing the cranial and middle mediastinal seg 
ments of the esophagus In addition there arc 
some small esophageal branches arising di 
rectly from the thoracic aorta destined to 
supply the caudal segment of the esophagus 
In the region of the aortic hiatus the cranial 
phrenic arteries usually two may originate 
from the thoracic aorta. 

There are usually 13 or 14 pairs of dorsal 
intercostal arteries of these eight or nine 
pairs anse from the thoracic aorta frequently 
by short common trunks which soon divide 
into the nght and left artery The dorsal cos 
toabdominal artery descends caudal to the 
last nb The first and second intercostal 
spaces do not contain a typical dorsal inter 
costal artery The first dorsal intercostal artery 
arises from the vertebral artery on the nght 
side and from the deep cervical on the left 
The second dorsal intercostal arteries ongi 
nate from the dorsal scapular The third 
fourth and fifth dorsal intercostal arteries 
arise from the supreme intercostal (a branch 
of the costocervical trunk or deep cervical on 
the left side) whereas on the right side the 
supreme intercostal artery anses mdepend 
ently from the nght subclavian and occa 
sionally from the deep cervical The supreme 
intercostal artery runs dorsally and caudally 
along the lateral aspect of the Iongus colli 
supplying same The third fourth and 


fifth dorsal intercostal artenes give off two 
slender dorsal branches supplying the longis 
simus thoracis 

Following separation each dorsal inter 
costal artery passes cramodorsally along the 
lateral side of the vertebral body and thus 
reaches the caudal border of the correspond 
mg nb About the level of the costovertebral 
joint it gives off the dorsal branch which close 
to the intervertebral foramen divides into 
spinal and muscular branches The spinal 
branch enters the vertebral canal via the 
intervertebral foramen and supplies the spinal 
cord and its meninges The muscular branch 
ascends dorsally through the lateral vertebral 
foramen and divides into a medial and lateral 
branch (Kahler 1960) The former passes 
along the caudal border of the spine of the 
corresponding vertebra and supplies the 
multifidus mterspinales rotatores and 
levatores costarum The lateral branch after 
coursing dorsally between the longissimus 
thoracis and spinalis thoracis supplies essen 
tially these muscles and the multifidus Ac 
cording to Kahler (1960) the dorsal branches 
do not supply the external skin Sometimes a 
dorsal intercostal artery is given off from that 
of an adjacent intercostal space 

In one case ninth tenth and eleventh dorsal Intercostal 
artenes arose by a common trunk at the lev el of the eleventh 
intercostal space (Kahler 1960) 

The dorsal intercostal artenes give off 
collateral branches which split into medial 
and lateral branches The medial branch 
passes laterally between the longissimus and 
iliocostahs thoracis while the lateral branch 
runs along the ventral border of the iho 
costahs thoracis Both of them supply the 
preceding muscles and the serratus dorsalis 
craniahs and caudahs and frequently also the 
cutaneus trunci and skin The distal continua 
tion of the dorsal intercostal artenes inside 
the respective intercostal spaces is typical 
Each of them releases a lateral cutaneous 
branch which after piercing the serratus 
ventrahs thoracis and obhquus extemus ab 
dominis supplies them and the pectornhs 
ascendens including the skin of the ventral 
abdominal wall Inthefemale it also vascular 
izes the thoracic mammary complexes (rami 
mammaru) The dorsal costoabdominal artery 
is small and after running a short distance 
along the caudal border of the last nb it is 
expended inside the transversus abdominis 
The last three or four dorsal intercostal ar 
tenes supply the costal part of the diaphragm 
(rami phrentci) As previously mentioned 
the dorsal intercostal artenes of the first two 
intercostal spaces do not develop typically 
and therefore they usually do not anasto 
mose with the corresponding ventral branches 
of the internal thoracic artery The dorsal 



44 -PORCINE HEART AND ARTERIES 


1327 



FIGURE 44-10. \rteries to the \entral wall of the trunk of the sow (schematic). 


1 Abdominal aorta. 2, cranial abdominal a , 2 , caudal phrenic a . 2". continuation of 2. 4. renal a (left), 5, ovarian a , 9, 
external iliac a , 10. deep circumflex iliac a , 11. medial circumflex femoral a . 12, cremaster a . 13, pudendoepigastnc 
trunk, 14, caudal (deep) epigastric a , 15. external pudendal a 16, lateral cranial branch of 15, 17, middle cranial branch 
of 15 * 18! medial cranial branch oi 15 21 to 23, cranial scrotal branches. 33. internal iliac a . 79. median sacral a . 80. 
caudal mesenteric a . 81 cranial rectal a 83. subclavian a , 83 , superficial cervical a , 84, internal thoracic a and v 85, 
ventral intercostal branches or 84. 86 sternal branches of perforating branches of 84. 87. cranial epigastric a , 88. lateral 
branches of 87. 89. medial branches of 87. 90. musculophrenic a . 91, external thoracic a . 92, prescapular branch, 93, 
dorsal intercostal aa . 94. cranial vena caxa, 94 , costocervical trunk 95, external jugular \ , 96. Aproxlmal axillary v . 96 , 
^distal axillary \ , N, mammary (superficial inguinal) lymph nodes, I - XIV nbs (From Nunez and Getty, 1969 ) 


intercostal arteries of the third to fifth or 
sixth intercostal spaces anastomose with the 
corresponding ventral intercostal branches 
off the internal thoracic, the seventh and 
eighth with similar branches of the musculo- 
phrenic, and the remaining with the ventral 
intercostal branches ofT the cranial epigastric 
artery (Fig. 44-10) The dorsal costoabdominal 
artery anastomoses variably with the cor- 
responding ventral branch off the cranial 
epigastric artery. 


ABDOMINAt AORTA 

The cranial abdominal artery arises on 
either side slightly cranial to the correspond- 
ing renal artery about the level of the third 
lumbar vertebra (Fig. 44-10). It passes to the 
lateral abdominal wall lying on the sublumbar 
muscles. At the lateral border of the psoas 
major it divides into a cranial and caudal 
branch. After following the caudal border of 
the last rib the cranial branch supplies the 
transversus abdominis and sometimes Use 
obllquus externus abdominis. The caudal 
branch likewise supplies the preceding mus- 
cles. The cranial branch anastomoses with the 
lateral branch of the cranial epigastric artery; 
whereas the caudal branch anastomoses with 
the medial branch of the caudal epigastric 


artery and the cranial branch of the deep cir- 
cumflex iliac artery (Kahler, 1 960). 

The lumbar arteries frequently number six 
pairs, but may vary between five and seven 
pairs depending on the breed The first five 
pairs usually arise from the dorsal wall of the 
abdominal aorta while the sixth (sometimes 
seventh) pair arises from the median sacral 
artery. The right and left lumbar arteries 
within the first four segments arise sepa- 
rately, but they frequently arise by a common 
trunk in the last two (or three) lumbar seg- 
ments At the level of the corresponding ver- 
tebral body each lumbar artery gives one or 
two small branches to the sublumbar mus- 
cles. It continues its ascent and near the inter- 
vertebral foramen releases the spina! branch 
for, the spinal cord and its meninges. After 
passing through the lateral vertebral foramen 
at the base of the transverse process it divides 
into a media! and lateral branch, supplying 
the epaxial muscles. 

The median sacral artery is the continuation 
of the abdominal aorta in the -sacrocaudal 
region (Figs. 44-10, 11 and 12) It arises be- 
tween the two internal ihacs at the level of 
the sacral promontory’ and passes caudo- 
dorsally along the peUic surface of the sa- 
crum On its course it gives off paired seg- 
mental sacral branches (Tig 44-13) which 
. enter the vertebral canal through th»» 


PORCINE 


1328 

sacral foramina and supply the spinal cord 
and its menint.es (ram t spmales) (Fig 44-14) 
Each sacral branch releases a slender dorsal 
branch which after emerging through the 
dorsal sacral foramen ramifies in the cpaxial 
muscles The fourth sacral branch frequentl> 
arises by a common trunk at the level of the 
first caudal \ertebra and beyond this lt\ el 
the median sacral continues as the median 
caudal artery to the up of the tail 
The median caudal artcrj courses along the 
ventral surface of the caudal vertebrae (Fig 
44-13) Ijmg inside the vascular groove be 
tween the sacrocaudalis ventrahs mediahs 
of both sides During its course it releases 
paired segmental caudal branches which soon 
divide into v entral and dorsal branches These 
branches anastomose with the corresponding 
adjacent ones forming the v entrolateral caudal 


and dorsolateral caudal arteries They pass 
along the ventral and dorsal aspects of the 
transverse processes of the caudal vertebrae 
After giving of! the ventral and dorsal 
branches the caudal branches pass dorsally 
supplying the dorsal muscles of the tail 
The} anastomose with the corresponding 
branches of the opposite side along the dorsal 
midline Small twigs are given off along the 
ventrolateral aspect of the tail ramifying in 
the fascia fat and skin of the adjoining area 
By means of arteriovenous anastomoses the 
corpora caudaba arc formed in this region 
Beyond the level of the fifth caudal vertebra 
the caliber of the median caudal artery is 
relatively small 

The celiac arterj is unpaired and arises 
from the ventral aspect of the abdominal aorta 
about the level of the last thoracic and first 



A Tcstitle 8 epididymis C ductu* deferens D seskuUr aland F bulbourethral eland r « r . 

H cius or penis (cut away from Uchlatic arch) 1 bulbospongiosu* j Isch oca K P 

W preputial d senlculum N scrotal (superf dal Inguinal) lymph nodes (lifted) O urinary bidder 
Ster R ureter S sphincter aniextemus 1 abdominal aorta 2, crania! abdominal a. 3 1 u mbarta. 4 VrS a Tie ft > s 
ticubr a 6 ureteric branch of 5 7 arterial cone and pampiniform plexus 8 testicular branches fl f ‘in' 

deep circumflex Hue a 11 medial circumflex femoral a. 12 . cremaster a. 13 pudendo^S£? t ® ' 

epigastric a 15 external pudendal a 10 lateral cranial branchof 15 17 m ddle cranlaf branch of 15 l^m^dufrran'ul 

branch of 15 19 arterial semicircle of prepuce 20 recurrent a. (left) of 18 21 caudal branch of IS 

branch of 21 23 deep branch of 21 25 anastomosis of 15 with CO 28 obturator branch of 11 31 

Of 11 33 internal iliac a. 31 umliltcala. 35 cranial vestcal a. 36 ^ of ductus deferens 37 u!e“ ri c bX h t 3 f 

cranial gluteal a. 39 ©bturatora. 10 urogen tala. 41 cranial branchof 40 42. prosiatlc branch 43 arteriaTarrh fntmrd 

by 42 and 49 44 arterial arch formed by 42 and 51 45 branches to prostate from 43 and 44 46 arlt^Lw 0 rlf°7^he 

urethra 47 caudal t esical a 48 u ret enc branch of 41 49 branch to vesicular gland 50 branch of ductu ■ deferrns Si 

caudal branch of 40 52 anastomotic branches from 51 to 42 S3 anastomotic branches from Si to co S 4 

of 53 55 ventral branches of 53 60 internal pudendal a. 61 a of bulb of penis 62. deep a. of penis 63 muscular 

branches 67 branch to anastomose with 1 5 74 caudal gluteal a 75 caudal rectal a 7G dorsal perineal a 77 branch to 

bulbourethral gland 78 branch to coccygrus 79 median sacra] a. 80 caudal mesenteric a 81 cranial rectal a (From 



44 -PORCINE HEART AND ARTERIES 


1329 



A, Ovary, B, ovarian bursa, C, uterine tube, D. uterine horn. E, body of uterus, F, \agina, G, vaginal vestibule, H, crus 
of clitoris (cut away from ischial arch), L. coccygeus m N, mammary (superficial Inguinal) lymph nodes (lifted); O, 
urinary bladder, P, rectum. R, ureter S, sphincter nni externus m . T, urethra, U, constnctor vestibull m , V, constrictor 
vulvac m , X, broad hg (cut away from its origin). 1 , abdominal aorta, 2. cranial abdominal a , 4, renal a (left), 5, ovarian 
a , 5 , tubal branches, 5*. (cranial) uterine branch, 6, ureteric branch, 7. pampiniform venous plexus, 8, continuation Of 5, 
9, external iliac a . 10, deep circumflex Iliac a , 11, medial circumflex femoral a , 12, cremaster a , 13, pudendoepigastric 
trunk, 14, caudal (deep) epigastric a., 15, external pudendal a , 16, lateral cranial branch of caudal superficial epigastric, 
17, middle cranial branch of caudal superficial-epigastric, 18, medial cranial branch of 15 21, 22, 23, cranial labial 
branches, 25 anastomosis between 15 and GO, 28, obturator branch of 11, 29. 30, branches of 28, 31, caudoproximal 
branch of! 1 , 32, continuation ofl 1 , 33, internal iliac a . 34, umbilical a , 35, cranial vesical a 36, uterine a ; 36 , continu- 
ation of 36, 36*, primary branches of 36. 36" , secondary branches of 36, 36 lv , branches to broad hg of uterus, 36*. anas 
tomotic branch to 5“, 36' 1 , anastomotic branch to 50 36'", uterine branches, 37, ureteric branch of 36, 38, cranial gluteal 
a , 39, obturator a , 40 urogenital a 41, cranial branch of 40, 42, vaginal branches of 41. 43. urethral branch of 41, 47, 
caudal vesicular a , 48, uretenc branch, 50, 50‘, (caudal) uterine branches, 51, caudal branch of 40, 53, anastomotic 
branch from 51 to 60, 60, internal pudendal a . 61, urethral a ,61 .anastomotic branch to 51, 62, common trunk to62‘ and 
62*, 62 , \estibular branches, 62*, deep clitoral a„ 63, a of the vestibular bulb, 68, dorsal chloral a , 74, caudal gluteal a , 
75, dorsal perineal a , 76, caudal rectal a., 78, branch to coccygeus m , 79, median sacral a , 80, caudal mesenteric a , 81, 
cranial rectal a (From Nunez and Getty, 1969 ) 


lumbar vertebrae between the crura of the 
diaphragm. It is 1 to 2.5 cm long and courses 
caudoventrally on the lesser curvature of the 
stomach It primarily divides into the hepatic 
and splenic arteries. 

Smollich and Berg (1960) observed, in one instance out 
or 155 feti, that both hepatic and splenic arteries nrose 
directly from the abdominal aorta 

The caudal phrenic artery arises from the 
initial segment of the celiac and is destined 
to supply the medial crus of the diaphragm. 
The origin of the cranial adrenal (suprarenal) 
branches is variable, arising either from the 
caudal phrenic or directly from the abdominal 
aorta. 

The hepatic artery is the larger of the two 
terminal branches of the celiac. It passes 
cranio ventrally and, ventral to the caudal 
vena cava, it extends to the lesser cu nature 
of the stomach, between the cardia and 


pylorus, and divides into the following 
branches. The origin of the following vessels 
may differ considerably between specimens. 

a The pancreatic branches, numbering four 
to seven, after separating from the hepatic 
artery pass caudoventrally and supply the 
body and adjacent cranial segments of both 
right and left lobes of the pancreas. Some- 
times the pancreatic branches represent one 
to two vessels at their origins which, after 
splitting into several branches, ramify in the 
pancreas 

b The right lateral branch is the most 
slender of all hepatic vessels. It supplies the 
caudate process of the caudate lobe of the 
liver (a. lobi candnti), and parts of the right 
lateral and right medial lobes or the liver. 
Frequently it furnishes the nutritive blood 
supply to the caudal vena cava which is en- 
closed here by the caudate process (SchUtsky, 




1330 


PORCINE 



FIGURE 44-13. Ventral view of sa- 
crocaudal region of pig. 

B. Sacrum, B , sacral promontory, C, cau- 
dal vertebra 1, D, caudal vertebra V, E. os 
coxae; F. ischtatie tuber, G, pubis (shown 
transparent to illustrate caudal vertebrae), 1, 
median caudal a . 2. median caudal v ; 3, 
median sacral a ; 4. median sacral v.; 5, 
sacral branches, 0 . origin of fourth sacra! 
branches, 7, fourth (left) sacral branch and 
7\ nght. 8, dorsolateral caudal a.; 9, ventro- 
lateral caudal a (From Cetty and Ghoshal, 
19G7.) 


c. The gastroduodenal artery arises from 
the right side of the hepatic. After coursing 
vcrttrally through the pancreas, it arrives at 
the cranial part of the duodenum. U gives off 
five to nine pancreatic branches which, after 
coursing cranially. vascularize a part of the 
right lobe and ‘the body of the pancreas. The 
gastroduodenal artery releases one to four 
pyloric branches, ramifying in the lesser 
curvature of the stomach and the pylorus. At 
theangle of divergence of the nght pancreatic 
lobe from the body it divides into the cranial 
pancreaticoduodenal and right gastroepiploic 
arteries. 

(1) The cranial pancreaticoduodenal artery 
ascends caudodorsally on the nght side be- 
tween the cranial part of the duodenum and 
the right pancreatic lobe, being surrounded by 


both layers of the mesoduodenum. It releases 
several small branches to the pancreas on the 
left and to the cranial and descending parts 
of the duodenum on the nght. The pattern of 
branching may differ greatly between indi- 
vidual specimens. 

(2) The right gastroepiploic artery passes 
cranioventrally on the right side. It crosses 
ca udo ventral I y the cranial part of the duo- 
denum near the pylorus, giving off several 
branches to them. It courses for a distance 
along the greater curvature of the stomach 
and gives numerous short gastric branches to 
the panetal and visceral surfaces of the 
stomach. Including the greater omentum- It 
anastomoses with the corresponding artery of 
the splenic. ' 

d. The right medial branch arises in the vi- 



44 -PORCINE HEART AND ARTERIES 


1331 



FIGURE 44-14 Sacrum and caudal aertcbrae of pig, lateral \iew 

1 , Median caudal a 2 median caudal v 3 median sacral a 4 median sacral % 5 sacral branches G origin of fourth 
sacral branches 7 fourth (left) sacral branch 8 doroso! Herd c ludul a 9 \entrolatcrd caudal a 10 dorsal continuation 
of caudal branch 11 dorsolateral caudal v 11 ventrolateral caudal % B sacrum C caudal vertebra 1 D caudal ver 
tebraV d sacrocaudahs dorsalis mcdialis e sacrocaudilis dorsalis lateralis f lntertransversanidorsalescaudac f inter 
transversarii ventrales caudae g sacroc mdahs ventralis lateralis h sacroc mdalls v entrails mediahs (From Getty and 
Ghoshal 1967) 


cinity of the preceding vessel and essentially 
supplies the nght medial, right lateral and 
sometimes the left medial, lobes of the liver 
It gives off the cvstic aitcrj, which after 
passing ventrally along the cystic duct rami 
fies in a variable manner on the gallbladder 
e The left (hepatic) branch is the largest of 
the hepatic vessels After coursing dorsally 
and left it divides into three branches Two 
branches supply the left lateral lobe and the 
other supplies the left medial lobe of the liver 
f The right gastric artery lies closely against 
the stomach wall Shortly after its ongin it 
releases two to four branches which ramify in 
the middle third of the parietal surface 
According to Sclultsky ( 1 966) an esophageal 
branch frequently arose (nine times out of 11 
specimens) from the nght gastnc artery 
which, after ascending on the cardia, supplies 
the caudal segment of the esophagus, anasto 
mosing with the esophageal branch of the 
thoracic aorta or the bronchoesophageal ar- 
tery 

The splenic artery is the other terminal 
branch of the celiac It passes to the left 
coursing along the dorsal extremity of the 
spleen where it is related to the left pancreatic 
lobe cramodorsally and the diverticulum of 
the stomach caudally From here it passes 
toward the visceral surface of the stomach 
being embedded in fat, and extends ventrally 
along the gastrosplenic kgament ( ramus gas 
trolienahs) It supplies the spleen, except a 
small dorsal portion which is vasculanzed by 
the short gastnc branches (Schiltsky, 1966) 
In addition, the splenic artery supplies the 
greater omentum and the splenic lymph 
nodes It gives off the following collateral 
branches 

a The left gastnc artery arises from the 
splenic, close to the origin of the latter from 


the celiac It courses ventrally toward the vrs 
ceral surface of the stomach and the adjacent 
part of the lesser curvature, where it divides 
into several branches The latter run ventrally 
along the visceral surface of the stomach to 
ward the greater curvature and thus supply 
the middle third of its visceral surface Occa- 
sionally they anastomose with the short gas- 
tnc branches of the nght and left gastroepi 
ploic artenes Sometimes, the esophageal 
branches arise from the left gastnc, extend 
over the lesser curvature of the stomach, and 
supply the caudal segment of the esophagus, 
anastomosing with the esophageal branch of 
the thoracic aorta or the bronchoesophageal 
artery 

b The diverticular artery anses cranially 
from the splenic, following the ongin of the 
left gastnc Occasionally it arises by a short 
common trunk with the left gastnc It supplies 
the diverticulum of the stomach 

c The pancreatic branch anses caudally, 
usually slightly distal to the ongin of the pre 
ceding vessel, from the splenic and passes on 
the left side It vascularizes the left pancreatic 
lobe 

d The left gastroepiploic artery anses from 
the splenic within the ventral half of the 
spleen It runs cramo\entrally inside the 
gastrosplenic ligament along the greater 
curvature of the stomach It gives fine 
branches to the gastrosplenic ligament and 
anastomoses with the corresponding right 
artery of the hepatic It releases several short 
branches along the greater curvature of the 
stomach 

The cranial mesenteric artery is unpaired 
and arises from the \ entral aspect of the ab 
dominal aorta about the level of the first lum 
bar \ertebra. Close to its ongin it is related 
cranially to the transverse colon, portal vein 



PORCINE 


1332 

and the body of the pancreas on the nght It 
passes somewhat caudoventrally and toward 
the left and gives off the following branches 
which may show individual variation in their 
origin 

a. The caudal pancreaticoduodenal artery 
arises from the caudal aspect of the parent 
vessel and soon divides into two branches The 
slender branch passes caudoventrally toward 
the duodenojejunal flexure whilethestronger 
one passes caudoventrally toward the caudal 
duodenal flexure Both of them course to the 
middle segment of the descending duodenum 
where they divide supplying the duodenum 
and the adjoining part of the pancreas 
b The jejunal arteries numbering 42 to 79 
anse from the parent vessel (Schiltsky 1966) 
They arc given off by the proximal segment of 
the cranial mesenteric artery on the nght side 
while In its caudal segment they are released 
both on the nght and left sides The first 
jejunal artery anses shortly distal to the ongm 
of the caudal pancreaticoduodenal and rami 
Fies In the duodenojejunal flexure It anasto- 
moses with the caudal pancreaticoduodenal 
and the second jejunal artenes The second to 
fifth jejunal artenes anse between the nght 
colic and the lhocccocohc (ileocolic) artenes 
on the right side and supply the initial segment 
of the jejunum The first ten jejunal artenes 
are rtlativ ely large the rest gradually decrease 
both in size and length The former ves 
sels divide into ascending and descending 
branches anastomosing with the adjacent 
vessels and forming arcades Beyond the 
tenth jejunal artery each gives three to six 
radiating branches which anastomose with 
the branches of other jejunal artenes They 
supply the jejunum and the mesenteric lymph 
nodes by means of small branches 

c The ileal arteries numbering two to four 
anse from the left and somewhat caudal as 
pect of the cranial mcscntcnc Shortly after 
their origins they divide and form a vascular 
network. One of the branches of the first ileal 
artery runs parallel with the ileum inside the 
mesentery anastomosing with the ileal mes 
enteric branch The ileal arteries in general 
supply two-thirds and the ileal mesemenc 
branch one third of the ileum (Schiltsky 
I960) 

d Theileoceeocolie(N A \ ileocolic) artery 
■arises from the left side of the parent vessel 
It passes vcntrally and shortly after its ongin 
giv es ofT the colic hranch According to Schilt 
sky (19G6) thececumliestransverselv cranial 
to the cnmal pelvic aperture when the 
stomach is empty therefore thcileocecocolic 
artery passes to the right and caudalty in the 
arch and runs crania! to the cccum whereis 
the colic branch lies on the left side and enters 
the ascending colon caudov emrally When the 
stomach is partially or completely filled the 
cecum lies on the left abdominal wall with its 


apex lying on the left side of the cranial pelvic 
aperture therefore the lleocecocohc artery 
courses caudally on the right side of the ce 
cum whereas the colic branch turns v entrally 
and to the left 

(1) The colic branch enters the ascending 
colon and follows its coils It also supplies the 
central flexure and the centripetal gyn Dorsal 
to the central flexure of the ascending colon 
it anastomoses with the nght colic artery 

(2) The cecal artery is the largest branch of 
the parent vessel It runs in the ileocecal fold 
to the apex of the cecum supplying its ventral 
band 

(3) The ileal mesenteric branch is relatively 
small and runs parallel with the ileum inside 
the mesentery It anastomoses with the first 
ileal artery and supplies the terminal part (ap 
proximately one third) of the ileum 

e The nght colic artery anses from the 
cramoventral aspect of the cranial mesentenc 
Sometimes it anses by a common trunk with 
the middle colic artery It supplies the centnf 
ugal gyn of the ascending colon and dorsal 
to the central flexure it anastomoses with the 
colic branch of the lleocecocohc artery In ad 
dition one or two small branches anse from 
its initial segment and supply the part of the 
transverse colon which adjoins the ascending 
colon 

f The middle colic artery may anse by a 
common trunk with the nght colic from the 
cranial mesentenc artery It passes cramodor 
sally to the left accompanies the transverse 
colon and supplies same by several fine 
branches It anastomoses with the left colic 
artery Sometimes the middle colic artery 
close to its ongin div ides into a branch cours 
mg on the descendingco/on and anastomosing 
with the left colic artery while the other runs 
toward the ascending colon and anastomoses 
with the nght colic artery 
The renal arteries anse from the lateral as 
pect of the abdominal aorta, slightly caudal to 
the ongin of the cranial abdominal (Figs 44- 
10 11 and 12) The nght renal artery anses 
somewhat more cranial than the correspond 
Ing left artery The nght renal artery passes 
along the dorsal aspect of the caudal vena 
cava and the nght adrenal gland and close to 
the hilus of the kidney it divides into several 
branches Dunng its course it gives small 
branches to the adrenal ( rami adrenales 
[supraremiles ] cuudales) the u reter (ramus 
h retericus) and to the capsule of the nght 
kidney The left renal artery passes dorsal to 
the adrenal gland and divides into several 
branches before entenng the hilus of the left 
kidney It gives identical branches to the 
adrenal gland and the ureter 
The testicular arteries anse slightly caudal 
to the ongms of the renal artenes from the 
abdominal aorta (Fig 44-11) They pnmanly 
supply the testicles and by means of col 



44 -PORCINE HEART AND ARTERIES 


1333 


lateral branches, also the epididjniis and the 
ductus deferens 

The o\nrian arteries are the homologue of 
the testicular arteries of the male (rigs 44-10 
and 12) Essential!), they supply ihcovancs, 
including the oviduct (ramus tiibnrws) and 
the cranial part of the uterine horn (ramus 
ii/enwws) 

The caudal mesenteric arter> is unpaired 
and arises near the termination of the abdomi 
nal aorta from its ventral aspect, at a lev el be- 
tueen the fifth and sixth lumbar vertebrae 
(Figs 44-10 and 12) After coursing caudo 
ventntlly it soon divides into its termin'*) 
branches on the dorsal aspect ol the descend 
ing colon The left colic arlerj, after coursing 
cramally in the mesocolon supplies the great 
or part of the descending colon b> means of 
sev cral small branches rrequcntl) itanasto 
moscs with branches of the middle colic ar 
tery near the transition of the transv ersc colon 
into the descending colon In the absence of 
the middle colic artery the left colic arter> is 
vveil developed supplies the area of vascular 
lzatton of the middle colic (Schiltsky 1966), 
finally anastomosing with branches of the 
right colic artery The cranial rectal arter> is 
larger than the preceding vessel After pass 
mg caudally, dorsal to the descending colon 
and rectum it divides into several branches 
supplying the terminal part of the descending 
colon, rectum, and anus (Figs 44-1 1 and 12) 
U anastomoses with branches of both caudal 
rectal artenes forming a delicate vascular 
network 

The internal iliac artcr> arises as a terminal 
branch of the abdominal aorta, about 1 to 1 5 
cm caudal to the origin of the external ihac,at 
the level of the last lumbar \ ertebra (Figs 44- 
11 and 12) It passes toward the cranial pelvic 
aperture along the lliacus and inside the pel 
vie cavity it lies between the preceding muscle 
and the intrapelvic part of the obturatonus 
externus It pierces the broad sacrotuberous 
ligament at the gieater ischiatic foramen and 
runs on the superficial surface of that liga- 
ment lateral to the ischiatic spine, toward the 
lesser ischiatic foramen where it ends by 
dividing into caudal gluteal and internal 
pudendal artenes During its course it gives 
off the following 

a The umbilical arlerv anses close to the 
origin of the parent vessel and runs along the 
lateral wall of the cranial pelvic aperture It 
courses lateially to the ureter and then some 
what cramally toward the lateral ligament of 
the urinary bladder, where it releases the 
cranial Vesicular arteries Its distal segment is 
obliterated iollowmg partuntion forming the 
round ligament of the urinar) bladder The 
umbilical artery gives off the deferential artery 
in the male which is homologous to the uterine 
artery in the female 


(1) The deferential arterj (a ductus defer- 
entis) anscs from the medial or caudal wall of 
the umbilical slight!) caudal to the origin of 
the latter After coursing craiuov cntrally, lat- 
eral to the v csicular gland, it releases a slender 
ureteric branch caudally for the ureter It pro 
cceds toward the deep inguinal ring, becomes 
incorporated in the spermatic cord and de- 
scends in the inguinal canal Inside the ingui- 
nal canal it divides into several branches 
v\ inch course toward the epididymis along the 
ductus deferens After passing between the 
medial surface of the epididymis and the 
lesUcJe ji pierces the tail of the epididymis 
The branches of the deferential artery anas- 
tomose with the testicular, forming the ac- 
cessor) testicular nrter> (Nunez and Getty, 
1969) 

(2) The uterine nrtcr> corresponds to the 
preceding artery of the male It arises from the 
umbilical almost at the same place as that of 
the deferential artery It follows a flexuous 
cramov entral course on the medial side of the 
broad ligament and, while traversing the deep 
face of the ureter it gives off the ureteric 
branch It advances in the broad ligament 
where it divides into several small branches, 
which anastomose with each other and ex- 
tend toward the lesser curvature of the 
uterine horn After dividing again they supply 
the uterine horns, the caudal third of the 
uterine tube, and the body and cervix of the 
uterus The branches of the utenne artery 
anastomose cramally with the (cranial) 
utenne branch of the ovanan artery and 
caudally with the (caudal) uterine branch of 
the urogenital artery 

b The iliolumbar arter) anses from the dor- 
solateral aspect of the parent vessel along the 
cranial border of the intrapelvic part of the 
obturatonus externus It supplies the lhacus 
and anastomoses with branches of the deep 
circumflex iliac and femoral artenes (Bick- 
hardt 1961) 

According lo Sisson and Grossman {1953} it gives off a 
branch tothequadneepsfemonsand lateral muscles of the 
thigh and ramifies in the nbdominat muscles It may also 
ghe origin to the caudal superficial epigastric artery which 
otherwise arises from the deep femoral 

The obturator arter) (Figs 44-11 and 12), 
according to N A V (1968), anses from the 
iliolumbar supplying the intrapelvic part of 
the obturatonus externus It anastomoses 
with the obturator branch of the medial cir 
cumflex femoral artery 
c The cranial gluteal arter> anses at the 
level of the greater ischiatic notch from the 
internal iliac and supplies the gluteus medius, 
gluteus accessonus and gluteus profundus 
and anastomoses with the deep circumflex 
iliac and sixth lumbar artenes, and the sacral 
branches of the median sacral artery (Koch 



1334 


PORCINE 



A Right testicle D right veslc-uUr gland F., provtnie gland F nghi bulbourethral gland C penis (sigmoid flexure) H 
crus of penis (cut away from ischiatlc arch) I butbospongiosus J lschlocavemosus (part removed) K, retractor penis 
(cut) N scrotal (superficial Inguinal) lymph node* (reflected) O unnary bladder P rectum R, ureter (cut) S sphincter 
ani extemu* T urethra (the sheath of the penis and the preputial sac were opened) 1 1 medial circumflex femoral a 15 
external pudendal a 16 lateral and 17 middle cranial branches of caudal superficial epigastric a. 19 arterial semicircle 
of prepuce 21 continuation of 15 22 23 cranial scrotal branches 24 branch to scrotal septum 25 anastomotic branch 
of 21 wnh CO 26 medial terminal branch of 21 and 22 27 lateral terminal branch of 21 and 22 28 obturator branch of 
11 29 30 branches Of 28 31 caudoprcrximal branch of 1 1 32 continuation of 11 33 internal iliac a. 38 caudal gluteal 
a. 39 obluratora 40 urogenital a. 41 cranial branch of 40 42, prosutic branch 43 arterial arch formed by 42 and 49 
44 arterial arch formed by 42 and 51 45 branches for prostate gland from 43 and 44 40 arterial network of urethra 47 
caudal vesicular a 48 ureteric branch of 41 49 branch to vesicular gland 51 caudal branch of 40 52 anastomotic 
branches from 51 to 42 53 anastomotic branches from 51 to 60 55 ventral branches of 53 56 medial branches of 53 
57 anaslomotlc branches from 46 to 28 58 dorsal perineal a. 59 branch to retractor poms GO internal pudendal a. 64 
perineal branches 65 branch to ischiourethrahs 66 anastomotic branches from 60 to 40 67 branch to anastomose with 
15 68 dorsal a. of penis 69 lateral branches of 68 70 branch to retractor penis 71 preputial branch of 68 72, superfi 
rial branch of 68 73 deep branch of 68 (From Nunez and Getty 1969) 


d The urogenital arter> arises from the 
ventral wall of the internal iliac opposite the 
origin of the cranial gluteal (Figs 44-11 12 
and 15) It divides into cranial and caudal 
branches on the lateral side of the vesicular 
gland in the male The crania! branch ramifies 
In the \ esicular gland and during ns cranio- 
ventral course ft gives off the following col 
laterals 

(1) The deferential branch (ramus ductus 
deferent ts) arises near the base of the vesicu 
lar gland passing tortuously on the medial 
face of the ductus deferens It supplies the 
cranial third of the ductus deferens and usual 
ly anastomoses with the deferential artery of 
the umbilical Frequently it arises by a com 
ttion trunk with the caudal \ esicular artery 


(2) The caudal vesicular arterj runs ven 
trally to the neck of the unnary bladder, con 
tnbuting branches to the artenal network 
around the urethra It usually gives off a 
slender uretenc branch to the medial face of 
the caudal end of the ureter 

(3) The prostatic branch is large and passes 
ventrally to the dorsal surface of the prostate 
gland where it divides into two branches One 
of them after coursing era move ntrally, anas 
tomoses with the collateral branch to the 
vesicular gland forming an artenal arch to 
the prostate gland (Nunez and Getty 1969) 
The other runs dorsocaudally and anasto- 
moses with the prostatic branches of the cau 
da] branch of the urogenital Some of them 
pass to the dorsolateral aspect of the urethra 



14— PORCINE HEART AND ARTERIES 


1335 


(ramus urethrahs }, forming an arterial net- 
w ork w Inch anastomoses with its fellow of the 
opposite side 

The caudal branch of the urogenital artery 
runs caudall> between the bulbourethral 
glands and gi\ es ofT a few branches cranio 
ventrally which after anastomosing with the 
prostatic branch, form an arterial arch, as 
mentioned previously It supplies the rectum 
by means of the middle rectal art on (« icc- 
tubs media) 

In the female, similar to the male the uro 
genital artery divides into cranial and caudal 
branches The cranial blanch courses caudo 
ventrally toward the cranial third of the vagina 
in the caudal bolder of the bioad ligament of 
the uterus It divides into seveial branches 

(1) The (caudal) uterine branch continues 
craniolaterally pieicing the lateral wall of the 
cervix and the body of the uterus Later it 
runs along the ventral aspect of the uterus 
and anastomoses with the branches of the 
utenne artery of the umbilical Sometimes the 
caudal vesicular artery arises together with 
the (caudal) utenne branch 

(2) The caudal vesicular arterv passes cram 
oventrally toward the neck of the urinary 
bladder, anastomosing with the cranial 
vesicular arteries off the umbilical It giv es off 
a slender ureteric branch laterally for the 
ureter and another urcthial branch for the 
cranial and middle thuds of the urethra 
The latter anastomoses with the urethral 
artery of the internal pudendal and from this 
anastomosis a delicate vessel in turn anas 
tomoses with the obturator branch of the me 
dial circumflex femoral artery (Nunez and 
Getty, 1969) 

(3) The \ ngmal branch runs caudally on the 
lateral wall of the vagina and after anasto 
mosmg with similar branches of the caudal 
branch of the urogenital supplies the cranial 
and middle two thuds of the vagina 
The caudal branch couises caudally along 
the dorsal suiface of the vagina and vestibule 
of the vulva supplying them and the rectum 
(a rectalu, media) 

e The dorsal perineal artery is the contmu 
ation of the caudal branch of the urogenital 
after the origin of the middle rectal artery, m 
both sexes (Fig 44-15) In the male it 
courses caudally between the bulbourethral 
glands where it gives off numerous branches 
to supply the gland and retractor penis mus 
cle and an anastomotic branch to the internal 
pudendal (Nunez and Getty 1969) In the 
Tennle, after passing medial to the vagina 
which it supplies it reaches the rectum and 
vulva It continues medial to the constrictor 
vestibuh to reach the constrictor vulvae, 
where it forms an arterial circle It supplies 
the ventral third of the sphincter am mternus 
and extemus, including the fat and skin of the 


perineal region Close to Its origin it releases a 
branch which, after coursing caudo ventrally, 
anastomoses with the internal pudendal 
(Nunez and Getty. 19G9) It gives ofT the 
caudal rectal artery in the female, supplying 
the caudal pait of the rectum, anus, and the 
coccygeus muscle As a variation, the dorsal 
penneal artery auses from the caudal gluteal 
In both sexes (Nune? and Getty, 1969) 

Variations exist bt tu cen the riRbt and left dorxal perineal 
arltrios of tin. sum specimen Sometimes one of them is 
better dt v eloped tlnn the other 

f Muscular branches, numbering three to 
six arise from the internal iliac near the lesser 
ischiatic notch One of them (n obturatoria) 
passes mediodistally After supplying the in 
trapehic part of the obturatonus externus, it 
anastomoses with the obturator branch of the 
medial circumflex femoral artery (Bickhardt, 
1961) Other branches vascularize in a van 
able manner the gluteus superficiahs, gluteus 
medtus gluteus profundus, and the pin 
formts According to Bickhardt (1961), one 
of these branches anastomoses with the cram 
al gluteal artery 

g The caudal gluteal arterv is one of the end 
branches of the internal iliac near the lesser 
ischiatic notch (Figs 44-11 and 12) Itdivides 
into several branches, supplying the gluteo 
biceps, ptnformis gluteus medtus, semiten 
dtnosus and semimembranosus It anasto 
moses with branches of the deep circumflex 
iliac and medial circumflex femoral artenes 
In the male, it may give origin to the caudal 
rectal artery. 

li The internal pudendal artery is the other 
terminal branch of the internal iliac near the 
lesser ischiatic notch (Figs 44-11, 12 and 15) 
or cranial to it It pierces the broad sacrotuber 
ous ligament and enters the retroperitoneal 
part of the pelvic cavity It passes caudoven 
trally over the obturatonus externus toward 
the ischiatic arch accompanying the satellite 
vein and pudendal nerve It gives off the fol 
lowing branches 

(1) Muscular branches to the mtrapelvic 
part of the obturatonus externus 

(2) The urethral artery passes cranially to 
the lateral wall of the urethra, where it anasto- 
moses with its fellow of the opposite side as 
well as the urethral branch of the urogenital 
artery, forming an arterial network 

(3) The v entral penneal artery passes dorso- 
caudally to the penneal legion, between the 
retractor penis muscle and the sphincter am 
extemus It supplies the ischiourethrahs and 
the fascia and skm of the ventral perineal re 
gion According to N A V (1968) in the boar, 
the caudal rectal artery anses from the ven 
tral penneal when it does not ongmate from 
the caudal gluteal Some of the branches of 



1336 

the ventral penneal ramify in the caudal 
scrotal wall (rami scrotales caudales ) 

The caudal rectal arterj has a variable on gin It may arise 
from the internal iliac (Blchhardt 19G1 ) and from thecau 
dal gluteal or internal pudendal (Nunez and Getty 19C91 


along the deep face of the sartorius and con- 
tinues as the femoral artery in the thigh The 
chief branches of the external Iliac artery are 
(Fig 44~16> 

1 The deep circumflex Iliac artery arises 
cm the parent % esscl and, after passing ven- 


(4) The artery of the penis is the continua 
tion of the internal pudendal around the is 
chiatic arch It divides into the artery of the 
penile bulb (a bulbi penis) the deep artery 
of the perns (a profunda penis), which sup 
plies the corpus cavemosum penis, and the 
dorsal artery of the penis The latter divides 
into nght and left branches beyond the second 
bend of the sigmoid flexure The left branch is 
relatively better developed than the cor- 
responding right, both nght and left branches 
give off a slender branch to the retractor 
penis muscle The left branch then courses 
ventrolaterally and. near the preputial fornix, 
it divides into the preputial, superficial, and 
deep branches The preputial branch pene- 
trates the preputial sheath and anastomoses 
with the external pudendal artery The super- 
ficial branch passes between the internal pre 
putial layer and the tunica albuginea of the 
penis, while the deep branch, after piercing 
the albuginea, ramifies in the corpus caver- 
nosum penis 

(4a) In the female the internal pudendal 
artery becomes the artery of the clitoris, near 
the ischiatic arch, which in a variable manner 
divides into the artery of the vestibular bulb, 
deep artery of the clitoris, and dorsal artery of 
the clitoris The artery of the vestibular bulb, 
after coursing caudally on the lateral v aginal 
wall, supplies the vestibular bulb After the 
preceding artery the vestibular branches 
anse (Nunez and Getty, 1969) and course 
caudally toward the constrictor vestibu 
li, anastomosing with the corresponding 
branches of the urogenital artery The deep 
artery of the clitoris arises from the caudal 
branch of the parent vessel or together with 
the vestibular branches It courses cranioven- 
trally toward the crura of the clitoris The 
dorsal artery of the clitoris continues the 
parent vessel ventral to the ischiatic arch and, 
after coursing caudally on the lateral wall of 
the body of the clitoris, enters it 

Someumes the dorsal artery of the clitoris of both side* 
arises by a common trunk from the left artery of the clitoris 
(Nunez and Getty 1969) 


PELVIC LIMB 

The external iliac artery arises from the ab 
dominal aorta ventral to the last lumbar verte 
bra, being somewhat cranial to the sacral 
promontory (Fig 44-10) It courses caudolat 
erad paralleling the medial face of the iliopso- 
as to the origin of the sartonus, where it turns 
ventrocaudad and leaves the abdominal cavity 
through the femoral ring Thereafter, it passes 



hranrh o- T, . . p clrc umnex SL, 2 .cranial 

522?*; c f uda J b , ranch 3 deep femoral a. 4 pud en 
‘ r V nk * • caudal (deep) epigastric a., 4% ex 
r 6 me< ? ial drcumn « femoral a., 6 , ob- 
turator branch 7 femoral a. 8 lateral circumflex femoral 
* • ? * “ e *eending branch of 8 8‘, continuation of 8 9 
attonofS* malleolar branches, II. confirm 

i k klera! Pknur iL 12 . accessory proximal 
perforating branch. 13 medial plantar a., M proximal per 
fora ting branch 20 descending genicular a.. 22, caudal 
J""”? ■£' 2 n branch. 22\ demand, 

JSfl ■JP' 1 "? 1 24 caudal Ublal 1 . 25 cranial 

M doraal common 

(pedal) digital a 11 (From Chotha] and Getty, 1968 ) 



1337 


44— PO KOINE HEART AND ARTERIES 


trolaterad along the \ cntral face of the iliopso 
as, it divides into a cranial and a caudal 
branch Close to its origin it gives branches to 
the lateral iliac lymph nodes Tlic cranial 
branch extends cramov entrallj on the deep 
face of the transv ersus abdominis, b> div iding 
into several branches it furnishes the preced- 
ing muscle, the obliquus mtemus abdominis, 
rectus abdominis tensor fasciae latac, and the 
fascia and skin of the flank region The caudal 
branch, slightly caudal to the coxal tuber, per- 
forates the abdominal wall and, on reaching 
the deep face of the tensor fasciae latae, di 
vides into several branches, supplying tint 
muscle, the rectus femons, vastus lateralis, 
gluteus medius, gluteobiceps, and the sub 
iliac lymph nodes It also vascularizes the 
fascia and skin of the flank rather extensiv ely 
2 The deep femoral arterj arises from the 
external iliac near the cranial border of the 
pubis It passes medial to the caudal head of 
the sartonus and somewhat ventral to the 
pecten ossis pubis between the iliopsoas and 
obturatonus extemus to the adductor, where 
it terminates into several branches The elucf 
branches are 

A The pudendocpigastric trunk anscs from 
the deep femoral medial to the caudal head of 
the sartonus and continues toward the deep 
inguinal nng where it divides into caudal 
(deep) epigastric and external pudendal ar 
tenes The preceding artenes may anse 
separately from the deep femoral without 
forming a trunk 

a. Tlie caudal (deep) epigastric artery passes 
along the deep face of the rectus abdominis 
After supplying that muscle it anastomoses 
with the cranial epigastric, cranial abdominal 
and deep circumflex iliac artenes It also 
anastomoses with the branches of the external 
pudendal Besides, it gives ofF the middle 
v esicular arterj to the unnary bladder 
b The external pudendal arterj descends 
through the inguinal canal emerging at the 
superficial inguinal nng (Fig 44-17) It gives 
off the caudal superficial epigastric artery 
which courses cramad along the superficial 
face of the rectus abdominis and supplies that 
muscle extensively, finally, it anastomoses 
with the cranial superficial epi gas tnc artery 
It gives branches to the spermatic cord, pre 
puce and scrotum in the male, whereas in the 
female it furnishes the caudal four mammary 
complexes and the penneum, where it anas 
tomoses with the internal pudendal The 
cremaster arterj is a slender vessel present in 
both sexes (Nunez, 1964) It has a vanable 
origin from the pudendoepigastnc trunk in 
reference to the deep femoral, deep circum 
flex iliac or external pudendal artenes It 
supplies the cremaster muscle in both male 
and female 

B The medial circumflex femoral arterj is 


the continuation of the deep femoral beyond 
the origin of the pudcndoepigastric trunk 
(Figs 44-11, 12, 15, and 16) It passes caudo 
distad through the adductor between the ap- 
posing faces of the semitendinosus and glu- 
teobiccps to the popliteal Ijmph nodes It 
gives collaterals to the pectmcus, obturatonus 
extemus, gluteobiceps, adductor, quadratus 
femons, gcmclh, semimembranosus, semi- 
tendinosus, and gracilis One of these branches 
anastomoses with the cranial gluteal artery 
on the lateral surface of the gluteus profun- 
dus 

The obturator branch is usually single and 
passes dorsocramad through the obturator 
foramen, supplies the intrapelvic part of the 
obturatonus extemus and coccygcus, and an- 
astomoses with the obturator arterj given off 
by the iliolumbar, internal pudendal, or the 
internal iliac In addition, the obturator 
branch anastomoses with the urogenital ar- 
terj (N A V a prostatica in the male or a 
vaq malts m the female) on the lateral wall of 
the urethra or with the muscular branches of 
the internal pudendal 

The femoral arterj is the distal extension of 
the external iliac m the pelvic limb beyond the 
femoral nng It passes between the two heads 
of the sartorius and descends in the femoral 
canal It continues through the popliteal re- 
gion and becomes the popliteal artery while 
coursing between the two heads "of the gas 
trocnemius Immediately after entenng the 
femoral canal it gives off branches to the 
lliacus, sartonus, pectineus, adductor, and 
semimembranosus Some of its branches 
anastomose with the iliolumbar and deep cir- 
cumflex iliac artenes Its chief branches are 
(Fig 44-16) 

1 The lateral circumflex femoral artery is 
large and, after coursing laterally for a short 
distance between the rectus femons and vas- 
tus medialis, it divides into a distinct ascend- 
ing and descending branch The former di- 
vides into several muscular branches along 
the deep face of the vastus lateralis for the 
quadneeps femoris, gluteus medius and pro- 
fundus, tensor fasciae latae, and gluteobiceps 
It anastomoses with the caudal femoral and 
descending genicularartenes near the patella, 
and also the deep circumflex iliac and caudal 
gluteal artenes Sometimes the nutnent ar- 
tery of the femur anses from it The descend- 
ing branch (former cranial femoral artery) 
courses distocramally and vasculanzes the 
rectus femons, vastus medialis, sartonus, and 
ibacus and anastomoses with the deep cir 
cumflex iliac artery 

2 The saphenous arterj is the most exten 
sive branch of the parent vessel It passes 
subcutaneously distoeaudad and, near the 
middle of the leg, it comes to be cranial to the 
common calcaneal tendon It descends along 



1338 


PORCINF 



Fl( LRF 44 17 External genitalia of male hog 


1 Obi quus extemus abdominis 2 prepu lalis cranial s 3 obi quui Intermix abdom n s 4 
rectus abdom nis 6 prepu ial d ven culum 7 glans penis 8 caudal superf al i> gai nc j 
scrotal lymph nodes 11 external pudendal vessels 12 caudal superficial ep gastr c vex i, 


trnns ersus abdo nir 
9 prepu u( s c-iud 1 


10 


the medial aspect of the calcaneal tuber and 
slightly distal to the preceding structure it 
gives off the medial malleolar branches which 
ramify on the dorsomedial aspect of the tarsus 
and anastomose with the dorsal pedal artery 
At this site it also releases the calcaneal 


branches which are distributed around the 
calcaneal tuber and in the fascia and skin on 
the lateral asj ect of the tarsus At the level of 
the sustentaculum tali the saphenous divides 
into medial and lateral plantar arteries During 
its course in the thigh and leg it detaches 


H— PORCINE HEART AM) ARTERIES 


1339 


several small twigs for the fascia and shin on 
the craniomcdtal aspect or the stifle joint, and 
the medial surface of the leg (rig 44-1 8> 
a At the lev el of the tarsocruml articulation 
the medial plantar artery gives off a medial 
branch winch opens in the plantar common 
digital artery II, near the fetlock joint, close 
to the origin of the latter Near the base of the 
large metatarsal bones it releases a deep 
branch which after coursing latcrad between 
the intcrossei muscles and metatarsus, anas 
tomoses with the lateral plantar artery, con- 
stituting the (proximal) deep plantar arch 
The superficial branch of the medial plantar 
artery, about the middle of the metatarsus, 
detaches the dorsal common (pedal) digital 
artery II (in the absence of a corresponding 
dorsal metatarsal artery) which, after pissing 
through the second intcrmetatarsal spice, ap 
pears dorsally and, slightly proximal to the 
fetlock joint and divides into dorsal proper 
(pedal) digital artenes II and 111 descending 
along the axial surface of the second and 
abaxial surface of the third digits, respee 
lively Dorsal (abaxnl) proper (pedal) digital 
artery III receives further extensions of the 
plantar branch of the proximal phalanx 
from plantar common digital artery III or 
from us axial terminal branch near the 
middle of the proximal phalanx The super 
ficial branch of the medial plantar artery 
descends along the medial face of the flexor 
tendons and, on the plantar aspect of the 
fetlock joint, forms the superficial plantar 
arch in a zig zag fashion, together with 
the medial branch oi the literal plantar 
artery On the plantar surface of the fetlock 
joints of the pnncipil digits both the super 
ficial and (distal) aecp plantar arches are 
connected with each otiiei 
(1) Plantar common digital artery II anses 
from the superficial branch of the medial 
plantar artery on the plantai aspect of the fet 
lock joint of the second digit and close to us 
origin, receives the medial branch of the 
medial plantar artery It soon divides into 
plantar proper digital artenes II and III 
coursing along the axial surface of the second 
digit and the abaxial surface of the third digit 
Plantar (abaxial) proper digital artery III re 
ceives the plantar branch of the proximal 
phalanx from the parent vessel or from its 
axial terminal branch (n diqitahs plantaris 
propria III) near the middle of the proximal 
phalanx It enters- the distal phalanx through 
a foramen to anastomose with plantar (abax 
lal) piopei digital artery 111 forming the 
terminal arch 

(3) Plantar common digital artery IV arises 
from the superficial branch of the medial 
plantar artery slightly distal to the preceding 
vessel On Us course it receives the lateral 
plantar artery and following a short course it 
divides into plantar proper digital artenes IV 



FIGURE 44-18 Arteries of distal part of right 
pchic limb of domestic pig, plantar s lew, schematic 


9 Saphenous a 11 continuation of 9 12 lateral plantar 
a 13 medial plantar a 14 proximal perforating branch 
16 distal perforating branch 17 deep plantar (distal) 
arch 18 plantar common digital a II 19 plantar com 
mon digital a III 19 plantar branch of proximal pha 
lanx 30 plantar proper digital aa. II and III 33 (pro* 
Imal) deep plantar arch 34 plantar metatarsal a tl 35 
plantar metatarsal a III 36 plantar metatarsal a- IV 37 
plantar common digital a IV 38 plantar proper digital aa' - ' 
IV and V 40 plantar proper digital aa. Ill and IV 41 j 
branch to bulbar region 42 plantar branch of proximal 
phalanx (From Choshal and Getty 1968 ) 


PORCINF 


and V descending along the abaxial surface of 
the fourth and axial surface of the fifth digits 
respectively Plantar (abaxial) proper digital 
artery IV receives the plantar branch of the 
proximal phalanx from the parent tessel or 
from its axial terminal branch (a dtgi tails 
plan tans propria IV) near the middle of the 
proximal phalanx After coursing along the 
abaxial surface of the fourth digit it enters the 
distal phalanx through a foramen Within the 
bone it anastomoses with plantar (axial) 
proper digital artery IV constituting the 
terminal arch 

(3) Plantar common digital artery III con 
tmues the superficial branch of the medial 
plantar artery along the plantar aspects of the 
fetlock joints of the main digtts Near the 
middle of the proximal phalanx it gives the 
plantar branches which after coursing deep 
to the flexor tendons along the plantar surface 
of the proximal phalanx anastomose with 
plantar (abaxial) proper digital arteries III 
and IV respectively Following their anas 
tomoses the plantar branches of the proximal 
phalanx extend further to the dorsomedial 
and dorsolateral aspects of the mam digits 
where they finally anastomose with dorsal 
(abaxial) proper (pedal) digital arteries III and 
IV respectively Subsequently plantar com 
mon digital artery III divides into plantar 
(axial) proper digital artenes III and IV 
which descend along the axial surfaces of tilt 
third and fourth digits Sometimes the plantar 
branches of the proximal phalanx anse from 
plantar (axial) proper digital artenes III and 
IV Close to the ongin of the preceding ves 
sels two interdigital artenes are given off 
which after traversing the interdigital space 
of the mam digits anastomose with the cor 
responding dorsal (axial) proper (pedal) digi 
tal artenes III and IV The other branchings 
and dispositions arc identical to those of the 
thoracic limb 

b The lateral plantar artery after obliquely 
crossing the superficial digital flexor tendon 
descends in the groove formed by the flexor 
tendons and the- long plantar ligament and 
anastomoses with the accessory proximal per 
forating branch (N A V a tarsea perforans 
proximalts ) of the dorsal pedal artery Slight 
ly distal to the base of the large metatarsal 
bones it gives an anastomotic branch which 
after coursing mediad between the metatar 
sus and the interossei muscles assists in the 
formation of the (proximal) deep plantar 
arch Near the middle of the metatarsus it 
detaches dorsal common (pedal) digital artery 
IV (in the absence of the corresponding dorsal 
metatarsal artery) which after traversing the 
fourth intermetatarsal space appears on the 
dorsal surface on the dtstalthitdoC this region 
Slightly proximal to the fetlock joint it divides 
into dorsal proper (pedal) digital arteries IV 


and V coursing along the abaxial surface of 
the fourth and axial surface of the fifth digits 
respectively The lateral plantar artery con 
tmues distally and somewhat proximal to the 
fetlock joint releases plantar metatarsal ar 
tery IV and empties itself in plantar common 
digital artery' IV on the plantar surface of the 
fetlock joint of the fifth digit The former de 
scends between the metatarsus and the Inter 
ossci muscles and contributes In the forma 
tjon of the (distal) deep plantar arch During 
its course the lateral plantar artery gives 
branches to the fascia and ligaments on the 
plantar aspect of the tarsus and the flexor 
tendons 

3 The descending genicular artery arises 
from the femoral slightly distal to the ongin 
of the saphenous (Fig 44-16) It passes era 
modistad along the caudal border of the vastus 
medialis and ramifies extensively within that 
muscle extending to the medial aspect of the 
stifle joint It also supplies the rectus femons 
and the skin cranial to the stifle joint Some 
times lateral to the patellar trochlea it anas 
tomoses with the descending branch of the 
lateral circumflex femoral artery 
4 The caudal femoral artery anscs from the 
femoral in the popliteal region before it 
passes between the two heads of the gas 
trocnemius Following a short course it divides 
into two branches 

a The ascending branch passes laterally and 
arrives at the deep surface of the gluteobiceps 
It gives branches to the preceding muscle the 
vastus lateralis adductor lateral head of the 
gastrocnemius and lateral aspect of the stifle 
joint Sometimes it anastomoses with the Iat 
era! circumflex femoral and popliteal arteries 
b The descending branch mainly supplies 
the gastrocnemius and the flexor digitorum 
superficialis and sometimes the, superficial 
popliteal lymph nodes On the lateral aspect 
of the calcaneal tuber it anastomoses with the 
saphenous 

The popliteal artery continues between the 
two heads of the gastrocnemius to which it 
gives a branch finally dividing into cranial 
and caudal tibia! artenes deep to the popliteus 
(Fig 44 16) Dunng its course it vanably 
gives off the lateral proximal middle and lat 
eral and medial distal genicular arteries at the 
level of the femoral condyles They supply in 
general the menisci joint capsule penchon 
dnum and the fat under the patellar liga 
ments The lateral proximal genicular artery 
anastomoses with the caudal femoral popbte 
al and cranial tibial artenes (Bickhardt 1961 
Koch 1965) 

1 The cranial tihial artery assumes the dis 
tal continuation of the popliteal and after 
piercing the crural interosseous membrane 
appears on the cranial surface of the leg. 
After emerging through the interosseous 



PORCLNE 


1342 

proximal phalanx divides into dorsal (axial) 
proper (pedal) digital arteries III and IV e* 
tending along the axial surfaces of the third 
and fourth digits Each anastomoses with the 
corresponding plantar digital artery by means 
of an mterdigital artery traversing the inter 
digital space 

2 The caudal tibial artery is the other ter 
minal branch of the popliteal At first it 
courses distallv between the popliteusand the 
flexor digiti I longus beneath the tibialis can 
dalis, and thereafter between the latter and 
the flexor digitorum longus It vascularizes 
all heads of the flexor digitorum profundus 


BlBUOGltAPHY 


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Koch T 1970 Lehrbuch der Velenn'ar Anatomle Band HI 2nd tdi 
tion. Jena VEB Gustav Fischer Verlag. 

Mall F P 1911 On the musculararchltecture of the ventricle, of the 

human heart Am. J Anat IJ 211 266 
Men J 1911 Uber die Arterien der Schulterextremltit voit Rind 
und Schweln mu besondcrer Beruck.lchtlgung lhrer Anlage 
Osterreichlsche Hochenschrlft furTierhellkun(!e34 35 93-151 
Nickel R. and R. Schwarr 1963 VergJeichendc Betrachtung der 
Kopfartcrien der Ilau.saugettere (Katie llund Schweln Rind 
Schaf Ziege Pferdk Zbt VeL Med 19(A) 69-120 
Nomina Anatomlca ‘Vetennana IbfeB International Committee on 
Vet AnaL Nomen. Vienna, Austria Printed by Adolf Holi 
hau.en t Successor. 

Nunez Q 1964 Blood ve.»et* of (he genitalia and accessory genital 
organ, of .wine M S Thesis Ames Iowa Library Iowa State 
University 

Nunez Q andR. Cetty 1969 Arterial supply to the genitalia and ac 
cessory genital organs of swine Iowa State J Sd44 93 126 
Prince Jll DC Dmem I EglitlsandC LRuvkell. I960 Anatomy 
and Histology of the Eye and Orbit in Domestic Animals. Spring 
field Charles C Thomas. 

Schlltsky R IX* Arterien dir Verd-ivut csoruane In Bauch und 
Beckenhohle elnschliesshch Leber Bauchspelcheldrusse und 
Milz de* Schwelnes Dissertation TierirzUiche HochKhule 
Hannover Germany 

Selim dt h 1910 Die Arterirllen hopfgefasse de* Rlndes Dl**erta 
non (Med VeLFakulUt) Zurich Switzerland. 

Schwarz R. 1959 Arterien und Venen am Kopf der Ziege Distena 
lion Tieramliche HochKhule Hannover Cermany 
Schwarze E and L Schidder 1964 Kompendium der VeterinJr 
Anatomic Band 111 Jena VEB Custav FUcher Verlag 
Shaner R, F 1928 The development of Ihe muscular architecture 
of Ihe ventricles of the pig s heart, with a review of the adult 
1 earl and a note on two abnormal mammalian hearti AnaL Rec 
39 1 33 


Sisson S and J D Pressman 19o3 The Anatomy of the Domestic 
Animals 4th ed Philadelphia VV B Saunders Company 
Smolhch. A and P Berg 1960 Sytfrmat velie Untersuchunger 
liber Ursprung und Aufzwelgung der Aste des Aortenbogen 
beim tUutichu-ein (Sat tcrofa damrtttcuil Monatsr hefte fut 

Veterinarmedtzin 15 483 432 

Tandler J 1899 Zur V erglelchenden Anatomle der Kopfartcrien be 
den Mammalia. Dcnkvchr Akad Wis, Wien 67 677-784 
Zletzschmann, O fc. Ackemechl and H Crau 1943 EUcnberger 
Baum Handbuch der vrrglekhendra Anatomle der Haustiere 
18th ed Berlin Springer Verlag 



CHAPTER 


PORCINE 

LYMPHATIC 

SYSTEM 

by L. I. Saar and R. Getty 


LYMPHOCENTERS OF THE HEAD 


MANDIBULAR LYMPHOCENTER 

Mandibular lymph nodes (Figs 45-1 
and 2) The mandibular lymph nodes are lo- 
cated at the caudoventral border of the man 
dible on the lateral side of the stemohyoideus 
muscle They are covered laterally by the 
cutaneous muscles and by the parotid gland, 
being situated ventromedial to the mandible 
and rostral to the mandibular gland Usu 
ally the lymph nodes are located ventral to 
the linguofacial vein, but often they extend 
to the dorsomedial side of the vein Usually 
they form a mass of lymph nodes 2 to 3 cm 
in length and 1 5 to 2 5 cm in width Affer 
ents arrive from regions of the mandible 
that include the skin, superficial and deep'* 
muscles in that area, entire tongue, mucous 
membranes on the floor of the mouth, ton 
sils, cheeks and the rostral third of the nasal 
cavity, rostrum and upper lip Efferent 
lymph vessels pass to the ventral and dorsal 
superficial cervical and to the accessory man 
dibuJar lymph nodes Occasionally some 
efferents go to the lateral retropharyngeal 
lymph nodes 

Accessory mandibular lymph nodes 
(Figs 45-1 and 2) The accessory mandib- 
ular lymph nodes are found ventral to the 
linguofacial vein where the vein terminates 
into the external jugular vein They are sit 
uated caudal to the mandibular gland on the 
stemomastoideus muscle and are covered 
Completely by the parotid gland Afferent 
lymph vessels come from all the areas de 
scribed for the affeients of the mandibular 


lymph nodes Afferents come also from the 
ventral portions of the neck and from the 
cranial (ventral) portions of the thoracic re- 
gion as well as from the mandibular lymph 
nodes Efferent lymph vessels go mainly to 
the ventral and dorsal superficial cervical 
lymph nodes Occasionally some efferents 
pass to the ventral group of the middle super- 
ficial cervical lymph nodes 


PAROTID LYMPHOCENTER 

Parotid lymph nodes (Figs 45-1 and 2) 
The parotid lymph nodes are situated ven- 
tral to the mandibular joint at the caudal 
border of the masseter muscle They are 
partly or completely covered laterally by the 
rostral edge of the parotid gland Usually two 
to eight lymph nodes are found which form an 
elongated conglomeration 2 5 to 5 0 cm in 
length and 0 5 to 1 5 cm in width Afferent 
lymph vessels come from the superficial and 
deep structures of the head, dorsal to a hon 
zontal line extended caudally through the 
commissure of the lips, including the skin, 
subcutis, muscles of the face and the region of 
rostrum, upper lip, cheeks, medial part of the 
auricles and the eyelids Efferent lymph ves- 
sels go to the lateral retropharyngeal and 
sometimes also to the dorsal or cranial group 
of the ventral superficial cervical lymph 
nodes 

RETROPHARYNGEAL 

LYMPHOCENTER 

Lateral retropharyngeal lymph nodes 
(Figs 45-1 and 2) The lateral retropharyn- 

1343 



1S44 


PORCINE 



FIGURE 45-1 Lymph flow of the head neck and shoulder region of swine 

Notice the Ntnph flov. from the subcutaneous injection sites of the head to l 2 and 3 An efferent from •* pa«es over 
the dorsal border of the brachiocophahcus lo 6 Efferents of 5 pass to 8 Afferents of 5 originate from the subcutis ot the 
thoracic limb 1 Mandibular Inn 2 parotid Inn 3 accessory mandibular Inn 4 lateral retropharyngeal Inn. 5 central 
superficial cert ical Inn 6 medial retropharyngeal Inn ^ dorsal superficial certtcallnn 8 8 middle superficial C 
\ical Inn 10 axillary In or first nb A masseter B brachiocephaltcus C trapezius D omotransversanus E pecto- 
raits profundus (prtsrapuiar portion) !l stemomastoidcus a linguofacial v b maxillary v c external jugular v a 
Internal jugular v e cephalic \ f axillary \ g superficial cerctcal \ thd thoracic duct trd tracheal duct (From 
Saar and Cetty 1904a 1 


peal ljmph nodes form a group of one or two 
lymph nodes along the dorsal caudal border 
of the parotid gland They are found caudal 
to the auricular \ etn on the brachiocephalicus 
(cleidomastoideus) muscle These lymph 
nodes are cov ered partly or completely by the 
caudal border or the parotid gland Often they 
are not clearly distinguishable from the era 
nial group of the ventral superficial cervical 
lymph nodes The size of the lymph node 
conglomeration vanes from 1 0 to 2 5 cm in 
length Afferent lymph vessels amve mainly 
from the parotid lymoh nodes skin and super 
ficial muscles of the dorsal portions of the 
head, the cranial one third of the dorsolat 
eral side of the neck, and from the external 
ear. the caudolateral side of the auncles and 
the superficial structures of the occipital 
parietal and temporal regions of the head 
including the eyelids Efferent lymph vessels 
go to the dorsal superficial cervical lymph 
nodes In a few cases an efferent may pass 
over the dorsal border of the brachiocephal 
icus muscle and follow the course on the 
medial face of the latter muscle to the medial 


retropharyngeal lymph nodes and occasionally 
to the ventral superficial cervical (cranial 
group) lymph nodes 

Media* retroph arv ngeai ivmph nodes 
(Figs 45-1 and 3) The medial retropharyu 
goal lymph nodes are located on the dorso- 
lateral face of the muscles of the pharynx. 
They arc located dorsal to the common caro 
tid artery internal jugular vein and vago 
sympathetic trunk These lymph nodes are 
found just caudal to the hyoid bone and ex 
tend 2 cm ventromedial to the wing of the 
atlas Laterally they are covered by fat, the 
thymus (when present) and the tendon of 
the stemomastoidcus muscle, which struc 
tures, m turn, are covered laterally by the 
cleidomastoideus muscle Usually the lymph 
node presents an oval conglomeration 2 to 3 
cm in length and 1 5 cm in width Afferent 
lymph v essels come from muscles of the head 
and neck, the hard and soft palates, caudal 
half of the nasal cavity, sinuses, tonsils and 
the muscles of the larynx and pharynx Oc 
casionally afferents may be received from the 
lateral retropharyngeal, and dorsal and 



45 -PORCINE LYMPHATIC SYSTEM 


1345 


FIGURE 45-2. Superficial Ijmph flow 
of neck and thoracic limb of swine, lat- 
er view. 

I, Mandibular Inn , 2, parotid Inn , 3, ac 
cessory mandibular Inn , 4, lateral retro- 
pharyngeal Inn , 5, 5', ventral superficial 
cervical Inn , 7, dorsal superficial cervical 
Inn , 10, axillary in of first rib. A, mas 
seler, B, brachiocephalicus, C, trapezius, D, 
omotransversarius, E, subclavius, G, man 
dibular gland, H, sterootbyroJdeus, a, 
linguofacial v , b, maxillary v , c, external 
jugular v , d, internal jugular v , e, cephalic 
v , f, axillary v , g. superficial cervical v , 
th d , thoracic duct (From Saar and Getty, 
1964b) 



2 



FIGURE 45-3. Lymph flow of mammary glands of the sow. 


, l Medial retropharyngeal inn , 2. dorsal 2\ ventral, and 2". middle superficial cervical Inn . 3 axillary in of first rit, 4 
sternal Inn, S mammary Inn., 5‘, accessory mammary Irtn (From Getty, 1964 ) ' ’ 



1346 


PORCINE 


ventral superficial cervical lymph nodes 
Efferents join and form the tracheal trunks 


LYMPHOCENTERS OF THE NECK 


SUPERFICIAL CERVICAL 
LYMPHOCENTER 

Dorsal superficial cervical lymph 
nodes (Figs 45-1 through 5) The dorsal 
superficial cemcal Ijmph nodes are located 
cramodorsal to the shoulder jomt, cranial 
to the pectorahs cleidoscapsulans muscle, 
situated on the serratus ventralis The dorsal 
third of the conglomerate mass of lymph 
nodes is covered by the trapezius muscle, 
while the ventral portion extends under the 
omotransversanus Generally there is present 
only one oval shaped conglomerate of lymph 
nodes of variable size from 1 to 4 cm In length, 
although occasionally one or two smaller 
lymph nodes, 0 5 to 1 0 cm in size, may 
be present ventral to the main group, covered 
by the omotransversanus Afferents come 
from the skin subcutis, muscle3 of the 
neck and cranial half of the thoracic area, 
and From the skin and subcutis of the medial 
and lateral aspects of the thoracic limb, 
including all structures (muscles and joints) 
distal to the carpal joint Furthermore, 
afferents come from the parotid, lateral retro- 
pharyngeal, mandibular,' ventral superficial 
cervical and accessory mandibular lymph 



FIGURE 45-4 Lymph vessel connections of su 
perfieia! cervical snd axillary lymph node of the first 
rib, right side 


5 Ventral, 7 dorsal, and 8 8 , middle superficial cervical 
Inn. 10 axillary Inn of first nb c external jugular v d 
internal jugular v e cephalic v , f a xillar y v g tuperfi 
’cial cervical v (ascending branch) (From Saar and Getty 
1964a.) 


nodes Efferents form large sized lymph 
vessels along the superficial cervical vessels 
and terminate in the brachiocephalic vein 
Some of the efferents first pass to the middle 
cervical lymph nodes Occasionally an 
efferent may go to the medial retropharyngeal 
lymph nodes 

\ E VIRAL SUPERFICIAL CEIIVICAL LYMPH 

nodfs (Figs 45-1 through 5) The ventral 
superficial cervical lymph nodes form a row 
of lymph nodes on the ventrolateral side of 
the cicido-occipitalis muscle and on the lateral 
side of the cleidomastoideus muscle along 
the caudal border of the parotid gland They 
represent a chain of lymph nodes extending 
from the lateral retropharyngeal lymph 
nodes caudoventral along the cranial edge of 
the brachiocephalicus muscle Usually the 
lymph nodes seem to form two or three 
groups along the brachiocephalicus muscle 
which may be distinguished as the cranial, 
middle and caudal groups The cranial group 
is quite frequently not clearly distinguish 
able from the lateral retropharyngeal lymph 
nodes The middle group is usually composed 
of smaller lymph nodes less than 0 5 to 1 0 cm 
in size Occasionally some of these lymph 
nodes are found to cover an area dorsally on 
the cleido-occipitalis muscle reaching to the 
dorsal border of the omotransversanus, 
thus, located close to the dorsal superficial 
cervical lymph nodes The caudal group ap- 
pears to be represented by a large conglom 
eration of lymph nodes, approximately 2 to 
3 cm in length and 1 to 2 cm in width Affer- 
ent lymph vessels to the cranial and middle 
groups come mainly from the mandibular 
and accessory mandibular lymph nodes and 
occasionally are received from the parotid 
and lateral retropharyngeal lymph nodes, 
afferents are received by the cranial and mid 
die groups, from the caudal group of the 
ventral superficial cervical lymph nodes The 
caudal group of the ventral superficial 
cervical lymph nodes receives the super- 
ficial lymph vessels of the thoracic limb as 
well as from the lateral and ventral regions 
of the thoracic wall which, in females, in 
eludes the lymph vessels of the first two or 
three mammary glands Efferents go mainly 
to the dorsal superficial cervical lymph nodes 
Occasionally some efferents from the crani 
al group may pass to the medial retropharyn 
geal and from the caudal group to the ventral 
(prcup of the middle superficial cervical 
lymph nodes and, occasionally, to the axil 
lary lymph nodes of the first nb 
Middle superficial cervical lymph 
nodes (Figs 45-1, 3. 4, and 5) The mid 
die superficial cervical lymph nodes may be 
described as two inconsistently found groups, 
of which the first (dorsal) group (varying in 
size from 0 5 to 3 0 cm in length) is located 
along the course of the superficial cervical 



45— PORCINE LYMPHATIC SYSTEM 


1347 


FIGURE 45-5. Lymph flow of thoracic 
limb of swine, medial view. 

All ribs, except the first, have been re- 
moved 5', Ventral, 7, dorsal, and 8, middle 
superficial cervical Inn , 10, axillary Inn of 
first nb, 11, sternal Inn , B, brachlocepha 
Ileus, D, omotranstersanus, E, subclavius, 
E\ pectoralls dcscendens, E\ pectoralis 
transversus, L, supraspinatus O. subscapu 
Ians, P, teres major, Q, latissimus dorsi, R. 
cutaneus trunci, S, pectoralis ascendcns, 
c, external jugular v , d, internal Jugular v , 
e, cephalic v ; f, thoracodorsal v , f, subsca- 
pular v , g, ascending branch of superficial 
cervical h, subscapular a, j, thoracodor- 
sal v ; k, deep lymph vessels along brachial 
veins, m, external thoracic v (From Saar 
and Getty, 1964b) 



vein to its termination into the external jug- 
ular vein Cranially these lymph nodes can- 
not always be clearl/ distinguished from the 
dorsal superficial cervical lymph nodes. The 
second group is situated dorsal to the course 
of the external jugular vein, being covered 
laterally by the cleido-occipitalis and cleido- 
mastoideus muscles. The lymph nodes cannot 
always be clearly distinguished cranially 
from the ventral superficial cervical lymph 
nodes and caudally they often appear as be- 
ing "split off” lymph nodes of the axillary 
lymph nodes of the first rib. The dorsal group 
receives afferent s from the dorsal super- 
ficial cervical lymph nodes and from ad- 
jacent structures. Afferents to the ventral 
group come from the dorsal group and from 


the caudal group of the ventral superficial 
lymph nodes Efferents of both groups either 
join the tracheal trunks, empty into the 
brachiocephalic vein, go to the axillary lymph 
nodes of the first rib or to the caudal deep 
cervical lymph nodes. 


DEEP CERVICAL LYMPH O CENTER 
In swine this lymphocenter consists of 
small lymph nodes related to the trachea 
and extending from caudal to the larynx 
ventrad to the thoracic inlet. They are rela- 
tively small and inconsistently found and 
of less importance compared to the nu- 
merous and well developed superficial cer- 
vical lymph nodes in this animal. The deep 




I Axillary Inn. of fint rib 2 caudal deep cervical Inn. 3 eternal Inn. 4 cranial mediastinal Inn. 5 left tacbeobna 
chiallnn. C middle tracheobronchial Inn. 8 caudal mediaitlnal Inn. 9 thoracic aortic Inn. a. tracheab _e*ophatm , c. 
Internal Jugular v d. common carotid a. e external Jugular v f axillary v r. axillary tatemal thoracic v . i cranial 
vena cava j costocenical trunk k. thoracic duct m left vena azygo* n left chief bronchi o esophagus p thoracic 
aorta. (After Baum & Grau 1938 ) 


cervical lymph nodes form three groups 
which may be distinguished as cranial, mid 
die and caudal 

Cranial deep cervical lymph nodes 
The cranial deep cervical lymph nodes are 
situated in the region between the larynx 
and thyroid on the first and second tracheal 
rings (ventral to the internal jugular vein) 
These lymph nodes are usually absent. Their 
size vanes from less than 0 25 to 0 5 cm in 
length 

Middle cranial deep cervical lymph 
NODES The middle cranial deep cervical 
lymph nodes are located just dorsal to the 
thyroid, ventrolateral to the trachea. These 
lymph nodes are seldom found They may be 
easily overlooked because of their minute 
size 

Caudal deep cervical lymph nodes (Fig. 
45-6) The caudal deep cervical lymph 
nodes form an unpaired group of lymph nodes 
located caudal to the thyroid ventral to the 
trachea in an angle formed by the common 
jugular veins Usually there are three to 
eight small lymph nodes present of less than 
1 cm in size Laterally the lymph nodes are 
covered by the thymus The latter gland, 
when present, separates the caudal deep cer 
vical lymph nodes from the axillary lymph 
nodes of the firstnb 

The cramdl and middle deep cervical lymph 
nodes receive affe rents from the trachea, 
esophagus, larynx, pharynx, thymus and 
adjacent muscles Efferents pass to the cau 


dal deep cervical lymph nodes, or they empty 
into the tracheal trunks Afferents of the cau 
dal deep cervical lymph nodes come from 
the deep muscles of the neck, esophagus, 
trachea, thymus and thyroid, and from the 
cranial and middle deep cervical and occa 
sionally from the middle superficial cervical 
lymph nodes Efferents may go to the tracheal 
trunks, thoracic duct (left side), brachio- 
cephalic, or common jugular veins or, oc 
casionally, to the axillary lymph nodes of 
the firstnb 


LYMPHOCENTER OF THE 
THORACIC UMB 

AXILLARY LYMPHOCENTER 

Axillary lymph nodes of the first rib 
(Figs 45-1 through 6) The axillary lymph 
nodes of the first nb form a conglomerate of 
lymph nodes cranial to the first rib, being 
situated on the lateral side of the thymus, ven 
tial to the axillary veins Their size varies 
from 1 0 to 2 5 cm in length. Occasionally one 
or two small lymph nodes, less than 0 5 cm 
m size, may be found cranial to the main 
group along the lateral or ventral side of the 
external jugular vein. Thus, it is sometimes 
difficult to distinguish the latter lymph nodes 
from the middle superficial cervical and cau 
dal deep cervical lymph nodes Afferent 


45 -PORCINE LYMPHATIC SYSTEM 


1349 


lymph vessels come from all deep structures 
(muscles, tendons and joint capsules) of the 
thoracic limb. Afferents originate also from 
the cutis and subcutis distal to the carpus, 
including the bulbs of the claws., (Lymph 
vessels of the thoracic limb, distal to the 
carpus, enter the superficial cervical or 
axillary lymphocenters.) Efferents terminate 
in the brachiocephalic vein by forming nu- 
merous variations with the thoracic duct 
(left side), or with the efferents of the dorsal 
and middle superficial cervical and caudal 
deep cervical lymph nodes. 


LYMPHOCENTERS OF THE 
THORACIC CAVITY 


DORSAL THORACIC 
LYMPHOCENTER 

Thoracic aortic lymph nodes. The 
thoracic aortic lymph nodes are located in 
the mediastinum dorsal to the thoracic aorta 
and caudal to the sixth rib, usually in as- 
sociation with the azygos veins. The number 
and size of the lymph nodes vary greatly. 
Afferents arrive from muscles of the dorsal 
half of the thorax, pleura, mediastinum, and 
from the caudal mediastinal lymph nodes. 
Efferents go to the thoracic duct. 


VENTRAL THORACIC 
LYMPHOCENTER 

Sternal lymph nodes (Figs. 45-3, 5 and 
6). The sternal lymph nodes are situated 
ventral to the cranial vena cava in association 
with the internal thoracic vessels on the 
manubrium of the sternum. Their size varies 
from 3 to 5 cm in length. Afferent lymph ves- 
sels come from the muscles of the ventral 
half of the thoracic wall, the pectoral muscles 
and the obliquus extemus, rectus and trans- 
versus abdomini muscles. Afferents come 
also from the pleura, mediastinum and peri- 
toneum, and from the first two or three mam- 
mary glands. Efferents enter the common 
jugular or brachiocephalic vein or the tho- 
racic duct (left side). 


MEDIASTINAL 

LYMPHOCENTER 

Cranial mediastinal lymph nodes 
(Fig. 45-0). The cranial mediastinal lymph 
nodes are located In the prccardlal medi- 
astinum. Usually these lymph nodes are as- 
sociated with the trachea, the esophagus 
and the large blood vessels In this region, and 
they are often not clearly distinguishable 


from the sternal lymph nodes cranially and 
from the tracheobronchial lymph nodes cau- 
dally. The number of lymph nodes may vary 
from one to ten and the size from a few milli- 
meters to 2.5 cm in length. Afferents come 
from the muscles of the neck, shoulder and 
thoracic region, including the pectoralis pro- 
fundus muscle, the cervical part of the 
trachea, esophagus and thymus, pleura, medi- 
astinum and pericardial sac. Afferents are 
received from the thoracic aortic lymph nodes 
and from the bronchial lymphocenter. Effer- 
ents pass to the thoracic duct (left side), join 
the tracheal trunks or the efferents of the 
dorsal superficial cervical lymph nodes, or 
empty into the brachiocephalic vein. Some of 
the efferents may go to the sternal lymph 
nodes. 

Caudal mediastinal lymph nodes (Fig. 
45-6). The caudal mediastinal lymph nodes 
are found occasionally situated caudal to 
the aortic arch and along the esophagus; 
they number from one to three. Often these 
lymph nodes are not clearly distinguishable 
from the left and middle tracheobronchial 
lymph nodes. Afferents come from the 
esophagus and mediastinum; efferents ter- 
minate in the left tracheobronchial lymph 
nodes. 


BRONCHIAL 

LYMPHOCENTER 


Left tracheobronchial lymph nodes 
(Figs. 41-9 and 45-6). The left tracheo- 
bronchial lymph nodes are located cranial to 
the left apical bronchus on the left side of 
the trachea and medial to the left azygos 
vein. Cranially these lymph nodes may not be 
clearly distinguishable from the cranial 
mediastinal lymph nodes. Usually two to 
seven lymph nodes, 0.2 to 5.0 cm in length, 
are found. Afferents come from the lungs, 
trachea, heart and the caudal mediastinal 
and right tracheobronchial lymph nodes. 
Efferent lymph vessels pass to the thoracic 
duct or to the cranial mediastinal lymph 
nodes, or occasionally empty into the sub- 
clavian vein. 


(Fig. 41-9). The right tracheobronchial 
lymph nodes are located on the right (ven- 
tral) side of the trachea between the apical 
and middle bronchi. Usually there are one to 
three lymph nodes 0.3 to 2.0 cm in size. 
Afferents arrive from the lungs and trachea. 
Efferents go to the cranial left tracheobron- 
chial or cranial mediastinal lymph nodes. 
/^* IDI ^ E <T nAC , HEOnnONCI,IAI ' LYMPH nodes 
(Figs. 41-9 and 45-6). The middle tracheo- 
bronchial lymph nodes are situated in the 
angle formed by the bifurcation of the tra- 



1350 


PORCINE 


chea Their number vanes from two to 
five and their size from 0 3 to 2 5 cm in 
length AfFerents come from the lungs, 
trachea, esophagus, mediastinum and peri- 
cardial sac Efferents usually terminate in 


the left tracheobronchial or cranial medi- 
astinal lymph nodes 

Cranial nucitronuoNCiiiAt. iampii NOdis 
(Fig 41-9) The cranial tracheobronchial 
lymph nodes are located cranial to the apical 






. . „ „„ d , ngsels of abdominal viscera of awme 

FIGURE 45-8 Lymph nodes and coduod enal Inn 6 colic Inn 7 caudal mea 

1 Splenic Inn 7 cehac Inn 3 gn.tric Inn 4 hepa'mh “JijHnTn leional Inn a ,"«£! 

enteric Inn B lumbar aortic Inn 9 . ™5£.?5SjJ2edttr»Syli behind abdominaUorla) e lui^tiuns , K 


1 Splenic Inn 1 celiac Inn 3 gajtric lim a ‘“*“T 0 jeocollc Inn 11 jejunal inn a a™, 
enieric Inn 8 lumbar aortic Inn 9 medial Iliac Inn I hyll behind abdominal norla) e lui 

venacava c ponalv d thoracicdocKconlinuationofclsteiTia Jj > c0 , lc lnJ nk. j jejunal 

hunk terminating Into cistema chyli g celiac trunk n mice 
“Section of lymph flow (After Baum and Crau 19>*a > 


bronchus on the nght side of the trache 
Usually there are two to five lymph nodes 
J 4 to 3 5 cm m size Occasionally only one 
lymph node is present Afferent lymph ves 
sels come from the lungs, heart and ngm 
tracheobronchial lymph nodes Afferent 
Pass to the cranial mediastinal lymph node 
Pulmonary lymph nodes The pulmo- 
na r> lymph nodes are absent 


IYMPHOCENTERS OF the 

abdominal and pelvic wall 

lumbar LYMPHOCENTER 

L-UMBAn AOUTJC LYMPH NODES (Figs. 45-E, 
7 and 8) The lumbar aortic lymph nodes 


comprise a dozen or more smaU lymph nodes 
scattered along the ventral and lateral (of en 
Sal) sides of the abdominal aorta and the 
caudal vena cava They extend caudally from 
near the renal vessels to the caudal mesen 
tenc artery CrantaUy these lymph nodes ate 
often not clearly distinguishable from the 
renal lymph nodes, and caudally jt may be 
difficult to differentiate them from the me 
dial iliac lymph nodes The size of the lymph 
nodes vanes from a few millimeters to 2 cm 
in length Afferent lymph vessels come from 
the muscles of the lumbosacral region and the 
dorsal half of the abdominal wall, the pen 
toneum, urogenital organs and renal, phreni 
coabdominal, caudal mesenteric and medial 
and lateral iliac lymph nodes Efferent lymph 
vessels join the lumbar trunks or they pass 
to the cistema chyli. 

rfnal lymph nodes (Fig 45-7) The 



PORCINE 


1352 

renal lymph nodes are found in association 
with the renal vessels Usually there are one 
to four lymph nodes approximately 025 to 
1 5 cm in size They often are difficult to 
distinguish from the lumbar aortic lymph 
nodes Afferents come from the kidneys 
peritoneum adrenal glands, adjacent abdom 
mal and lumbar muscles and the phreni 
coabdommal lymph nodes Efferent lymph 
vessels pass to the lumbar aortic lymph nodes 
or they go to the cistema chyli 
Phremcoabdominal lymph nodes (Fig 
45-7) The phremcoabdominal lymph nodes 
are located caudal to the caudal branch of the 
phremcoabdominal vessels on the lateral 
side of the iliopsoas muscle, embedded in 
fat Occasionally these lymph nodes may be 
absent on one or both sides Their size varies 
from a few millimeters to approximate!* 1 
cm in length Afferent lymph vessels come 
from the peritoneum, abdominal muscles 
and lateral iliac lymph nodes Efferents go to 
the renal or lumbar aortic lymph nodes, or 
they pass to the lumbar trunks or empty into 
the cistema chyli 

Testicular lymph nodes The testic- 
ular lymph nodes are found, in the male, 
along the spermatic cord in association with 
the testicular vessels Their number, size 
and location vary greatly Some of the tes 
ticular lymph nodes are situated on the 
proximal part of the pampiniform plexus, 
some few minute lymph nodes are located 
along the course of the testicular artery, 
in a few cases lymph nodes are situated near 
the origin of the testicular artery where the 
latter vessel crosses the ureter The size 
vanes from a few millimeters to 1 5 cm in 
length Afferent lymph vessels come from 
the testis Efferents pass to the lumbar 
aortic, or to the medial iliac lymph nodes 


IUOSACRAI LYMPHOCENTER 

Medial iliac lymph nodes (Figs 45-7, 8 
and 9) The medial iliac lymph nodes are 
situated cranial and caudal to the on gin of 
the deep circumflex iliac artery along the 
lateral and medial aspects of the external 
iliac vessels Cramally the lymph nodes ex 
tend to the caudal mesentenc artery and 
often they arc not clearly distinguishable 
from the lumbar aortic lymph nodes The 
lymph nodes situated caudal to the deep 
circumflex iliac vessels are usually larger 
(up to 3 5 cm in length) The cranial group 
includes three to eight lymph nodes of van 
able size from a few millimeters to approxi 
mately 2 cm in length Afferent lymph ves 
sels come from the sacral, lateral iliac, cau 
dal mesentenc, testicular and anorectal 
lymph nodes and the inguinofemoral, ischi 
a tic and popliteal lymphocenters Further 


more, afferents come from muscles of the 
lumbosacral region and from the caudal half 
of the abdominal wall, deep structures 
(muscles, tendons, joints, bones) of the pel- 
vic limb which include the muscles of the 
hip, thigh, leg and foot, and from the tendons, 
ligaments, fasciae and joint capsules Effer 
ents form an extensile network in the region 
of the abdominal aorta and the caudal vena 
cava. They continue cranially to incorporate 
the lumbar aortic lymph nodes From this 
lymph vessel network one to three large- 
sized lymph trunks may arise, which may 
branch and join again and form collaterals 
These lymph trunks arc referred to as lumbar 
trunks They terminate in the cistema chyli 
Sacral lymph nodes (Figs 45-7 and 9) 
The sacral lymph nodes are located in the 
angle formed by the internal Iliac vessels, 
located near the origin of the medial sacral 
artery Usually there are one to three lymph 
nodes approximately 0 25 to 10 cm in size 
which appear to form an unpaired group of 
lymph nodes Afferent lymph vessels come 
from the muscles of the thigh and pelvic 
regions, tail, urinary and genital organs, 
and anorectal, urogenital, gluteal and Ischi 
atic lymph nodes Efferents terminate in the 
medial iliac lymph nodes 
Latfual iliac lymph nodes (Figs 45-7 
and 9) The lateral iliac lymph nodes are lo- 
cated cranial to the cranial branches of the 
deep circumflex iliac vessels They are Situ 
ated near the caudal edge of the abdominis 
trans\ersus muscle, embedded in fat on the 
ventrolateral surface of the iliopsoas muscle 
Usually there arc one to three small lymph 
nodes varying in size from several milli- 
meters to approximately 1 5 cm in length 
Occasionally these lymph nodes may be ab- 
sent on one or both sides Afferent lymph 
vessels come from muscles of the lumbo- 
sacral and abdominal regions and from the 
caudodorsal regions of the peritoneum 
Furthermore, afferents are received from the 
subiliac and occasionally, also, from the cau 
dal group of the medial iliac lymph nodes 
Efferents pass to the cranial group of the 
medial iliac lymph nodes, or they go in part 
to the phrenicoabdominal or lumbar aortic 
lymph nodes 

Internal iliac lymph nodes * The in- 
ternal iliac lymph nodes include the lymph 
nodes medial to the broad sacrotuberal hga 
ment in association with the branches of 
the internal iliac vessels However, in swine, 
there are no true internal iliac lymph nodes 
present, although occasionally there are 


The authors feel the term “Internal Iliac Inn." 1* more 
suitable than the N A-V 0973) term "hypogastric inn 
especially since the corresponding arteries and vein* are 
officially called the infernal iliac vessels 



45— PORCINE IA MPIIATIC SI STEM 


1353 


FIGURE 45-9 Lymph Row of 
pelvic limb of swine, medial mow 

1 12, Sublime Inn 13 superficial 
Inguinal Inn 14 14 superficial and 
deep popliteal Inn 15 gluteal Inn 
15 ischialic Inn 16 sacral inn 
17 17 medial iliac Inn 18 lateral 
iliac Inn h abdominal aorta m In 
temal Iliac a n middle sacral a o 
deep femoral V p femoral v q ven 
iral branch of deep circumflex iliac 
a. r external pudendal a. M e » 
ferenis of poplueal 1c M efTercnts 
of gluteal Inn (follow internal lilac 
vessels') O efTercnts of M (follow me 
dial circumflex femoral to deep fe 
moral vessels) P efferents from me 
dial side of limb along saphena 
magna (follow course of femoral ves 
sels) Q efferents of subillac Inn 
passing along deep circumflex Iliac 
vessels to medial and lateral iliac 
Inn R, efferents of superficial 
Inguinal inn. (follow course of exter 
nal pudendal vessels) (From Saar and 
Getty 1964c) 



small lymph nodes in both sexes wurogen 
Ital lymph nodes) in the urogenital fo 
association with the umbilical artery lv i tne 

female the urogenital lymph nodes are ‘ 
eated m the broad ligament of the 
m association with the proximal part ot 
ntnbdlcal artery Usually these lyi"P h 
? rc absent. In the male a small u ™f' n , „ 
fymph node of less than 0 5 cm in 
"«S be found on the dorsolateral side of tne 
es.cuHr gland in the urogenital fold 
* s lymph node is absent 


a vnnrrtAl. LYMPH NODES The anorectal 
1 rnnh nodes are situated along the dorsal or 
> mP l?°ml S aspect of the retroperitoneal 
d0 rtion o?the rectum Usually these lymph 
Sode° extend caudally 5 to 8 cm from the 
Crtmally they may not be easily dif 
? intiated from the caudal mesenteric 
S, nodes Their number vanes from two 
HS and their size from 0 2 to 2 2 cm in 
' th Occasionally these lymph nodes may 
be absenL Afferent lymph vessels come from 
the anus, rectum and muscles of the tail 



PORCINE 


1354 

Efferents pass to the sacral and medial ilfctc 
lymph nodes, occasionally also to the caudal 
mesentenc lymph nodes 
Uterine lymph node The utenne 1> mph 
node is found in the cranial part of the broad 
ligament of the uterus, associated with the 
utero ovarian vessels Usually there are one 
or two lymph nodes approximately 0 25 to 
2 0 cm in size Occasionally the lymph nodes 
are present on one side only, are completely 
absent or are difficult to distinguish from the 
lumbar aortic lymph nodes Afferents come 
from the ovanes and homs of the uterus 
Efferents go to the lumbar aortic lymph nodes 
or to the cistema chyli 


INGUINOFEMORAL 
(SUPERFICIAL INGUINAL) 

LYMPHOCENTER 

Superficial inguinal lymph nodes 
(Figs 45-3, 7, 9, 10 and 11) The super- 
ficial inguinal lymph nodes of the female are 
referred to as mammary lymph nodes They 
are situated ventral to the cranial branches 
of the external pudendal vessels along the 
lateral and caudal borders of the caudal half 
of the last mammary gland They represent 
an elongated, loosely arranged group of lymph 
nodes 3 to 8 cm in length and 1 0 to 2 5 cm in 
width 

In the male the superficial inguinal lymph 
nodes are called the scrotal lymph nodes 
They are located on the ventral side of the 
abdominal wall, lateral to the penis The scro- 
tal lymph nodes are associated mainly with 
the cranial branches of the external puden 
dal vessels which they cover ventrally The 
lymph nodes extend mainly craniolateral to 
the spermatic cord and to a lesser extent, 
caudomedially The lymph node conglom 
erate is approximately 3 to 7 cm in length 
and 1 to 2 cm in width 

Occasionally m the male and female a few 
accessory superficial inguinal lymph nodes 
are found 5 to 15 cm cranial to the main 
lymph node group along the subcutaneous 
abdominal vessels (Fig 45-3) Afferent lymph 
vessels come from the lateroventral half and 
the ventral part of the caudal half of the body 
and from the lateral (caudal) one third of 
the thigh and skin of the tail Afferents come 
also from the skin areas of the lateral aspect 
of the pelvic limb (distal to the stifle joint) 
and from the entire medial side of the pelvic 
limb including the deeper structures of the 
digits, accessory digits and bulbs of the claws 
Furthermore, afferents come from the 
rectus abdominis muscle and, in the male, 
from the skin and subcutis of the penis, pre 
putium, preputiales craniahs and caudahs 
and the subcutis of the scrotum In the 
female the mammary lymph nodes drain 



FIGURE 45-10 Lymph flow of pelvic limb of 
■wine, lateral view 


12, Subtllac Inn. 13 superficial inguinal Inn. 14 14 , 
superficial and deep popliteal Inn. 15 gluteal in 15 
ischlatic In M efferent* of popliteal 1c M efferent* of 
gluteal Inn. (Follow medial circumflex femoral to deep 
femoral vessel*) P efferents from medial *lde of limb 
along saphena magna (follow course of femoral vessels) 
Q efferents of subtllac Inn. passing along deep circumflex 
iliac vessels to medial and lateral lilac Inn R, efferent* of 
superficial inguinal Inn (follow course of external puden- 
dal vessels (From Saar and Getty 1964c) 

the subcutis of the vulva and the caudal 
four or five (out of six) mammary glands 
Occasionally afferents are received from the 
femoropateliar joint capsule Efferent lymph 
vessels follow the course of the external 
pudendal vessels (pudendoepi gastric trunk) 
to the deep femoral vessels and continue 
cranially along the external iliac vessels to 
the medial iliac lymph nodes 
Subiliac (prefemoral) lymph nodes 
(Figs 45—7, 9, 10 and 11) The subiliac 
ly mph nodes form aTarge, elongated conglom 
erate of small lymph nodes on the midline 
between the coxal tuber and the patella. 
They are situated cranial to the tensor fas 



45— PORCINE LYMPHATIC SYSTEM 



tutcutrKfod VeswH 


• IO|«tiC« Srt» 


flCURE 45-11. Subcutaneous lymph vessels on 
rae <H*l and lateral side or pelvic limb of swine, lat 
, eral view. 

12, Subiltac Inn.; 13. superficial Inguinal Inn.; <?• su P' r j 
Jieial popbteal In.; 14', deep popUteal In. (From Saar ana 
Ge «J, 1964c.) 

c iae latae muscle embedded in fatty sub 
cutaneous tissue along the ventral branches 
' °> 'be deep circumflex iliac vessels. Usually 
the conglomerate of the lymph nodes is2 to 
* ' :m in length and 1 to 2 cm in width, or 
sometimes there are two or three smaller 


1355 

lateral side of the broad sacrotuberal liga- 
ment 1 to 3 cm caudal to the cranial gluteal 
vessels, covered by the gluteus medius mus- 
cle Usually there are one or two, sometimes 
three lymph nodes. Occasionally these lymph 
nodes are absent on one or both sides. Their 
size varies from 0.2 to 1.5 cm in length. 
Afferents are received from the gluteal and 
popliteal lymph nodes Efferents go to the 
medial iliac and sacral lymph nodes. 

Gluteal lymph nodes (Figs. 45-9 and 10). 
The gluteal lymph nodes are situated 2 to 3 cm 
cranial to the caudal edge of the broad sacro- 
tuberal ligament, dorsal to the caudal gluteal 
vessels. In a few cases some of the lymph 
nodes are located near the ischiatic tuber. 
Their sire varies from 0.5 to 1.5 cm in lengtli. 
Afferents are received from the skin and the 
subcutis of the caudodorsal areas of the pel- 
vic region including the skin areas in the 
miv of the anus. Afferents also come 
S the accent muscles and from the 
nonliteal lymph nodes. Efferents go to the 
fscwatlc, Sal iliac and sacral lymph nodes. 


iymphocenters of the 

PELVIC LIMB 

ILIOFEMORAL IYMPHOCENTER 

"•’"VZ'pbnodusare loomed usSSy n't 
femoral •> P , tery near the origin of the 

the dSeSstS™k. These lymph nodes 
sometimes referred to as the deep inguinal 
lymph nodes, are absent. 


ou 'neumes there are two or tnree 
conglomerates of lymph nodes V Iese ” t ' 
Afferent lymph vessels are received from the 
“«n. subcutis and cutaneus trunci mu™ 
, , . lumbosacral, abdominal, pelvic 

mtgh regions. Cmniallv the drainage area 


“ *utimu5ui;rdi, auuuiiiu““t t — - 

_ - 1 regions. CraniaUy the drainage area 
extend to the eleventh or twelfth tho- 
racic vertebrae. In a few cases afferents are 
fuuetvcd from the femoropatellar joint cap- 
er m Eftcr c ntl ynph vessels follow the courae 
M the ventral branches of the deep circum- 
i ? X , Uiac vessels to the lateral and medial 
utac lymph nodes, 

,S CH1AT1C IYMPHOCENTER 

Tv^ttATtc lymph Nones (Figs. 45-9 and 10). 
" fuubiatic lymph nodes arc located on the 


POPUTEAI IYMPHOCENTER 

CytpftiFICIAL POPLITEAL LYMPH NODE 

E I*-9 10 and 11). The superficial 

oo S liteanympb umle is located on the dorso- 
P P !iil surface of the gastrocnemius muscle, 

rm l 3cm n from the skin, being embedded I in 
® m the small saphenous vein. The size 
■ lmm 05 to 3.0 cm in length, and oc- 

varies from 0-^^ sma]ler lymph node may 
casionaily veveIi j n exceptional cases 

bG p T re i,ra,'node group may be absent Affer- 
ent* lymph vessefs come from the skin and 
tcu!fs P of the caudolateral and plantar 
SU ms of the leg, distal to the tarsus, and in- 
«£* Se sibculis of bulbs and claws; 
? m *e dorsal surface of the digits and from 
me portion of the leg distal to the tarsus. 
Furthermore, afferents arrive from the mus- 
cifs Sons, ligaments and joint capsules 
Of the tarsus and digits. Efferents pass to the 
deep pSteal and medial Iliac lymph nodes. 



PORCINF 


1356 

Some of the efferents go to the gluteal and 
the ischiatic Jy mph nodes 
DtFP POPLITEAL LY MPH NODE (FtgS 45-9 
10 and 11) The diep popliteal Ijmph node 
is located approximate!) 3 to 6 cm eramodor 
sal to the superficial popliteal lymph nodes 
along the courses of the small saphenous 
vein, situated on the gastrocnemius mus 
cle between the biceps femons and semi 
tendinosus muscles The latter lymph node 
Is embedded in fat and often because of its 
small size (usuallv less than 0 5 to 0 75 
cm) it may be easil) overlooked Occasion 
ally there are two or three small lymph nodes 
In half of the cases however these lymph 
nodes are absent Afferents arrive mainly 
from the ^superficial popliteal lymph nodes 
but also from muscles of the adjacent areas 
Efferents pass to the medial iliac lymph 
nodes or some of them go first to the gluteal 
and ischiatic 1) mph nodes 


IYMPHOCENTERS OF THE 
ABDOMINAL VISCERA 


CEUAC LYMPHOCENTER 

IlFP VTJCfPODT VI ) LV WPJI NODES (Fig. 45-8) 
The hepatic lymph nodes are situated about 
the portal vein at the portal fissure They 
form a group of two to seven lymph nodes 
0 7 to 2 8 cm in size Afferent lymph vessels 
come from the liver, gallbladder, pancreas 
and pancreaticoduodenal lymph nodes 
Efferents go to the celiac lymph nodes or 
they join the celiac trunk 
SPLtstc LYMPH NODFS (Fig 45-8) The 
splenic lymph nodes are associated with the 
splenic vessels Some of these lymph nodes 
are located at the dorsal ponon of the splenic 
hilus (usually two to eight lymph nodes 0 2 to 
2 5 cm in size) while other lymph nodes are 
found along the course of the splenic artery 
near its ongin Often the splenic lymph nodes 
are not clearly differentiated from the celiac 
lymph nodes Afferents come from thespleen 
pancreas, stomach and omentum Efferents 
go to the celiac lymph nodes or terminate in 
the celiac lymph trunk 
Gastric lymph nodis (Fig 45-8) The 
gastric lymph nodes are situated at the cardia 
of the stomach being associated with the 
right gastric artery Usually there are one 
to five lymph nodes 0 3 to 4 0 cm in size 
Often they may not be clearly distinguishable 
from tlie celiac lymph nodes Afferent lymph 
vessels arrive from ihe stomach, pancreas, 
esophagus, mediastinum and diaphragm 
Efferents join to form large lymph vessels 
(gastric trunk) and terminate tn the celiac 
lymph trunk. 


Pan cre vti coduodfn al lymph nodls 

(Fig 45-8) The pancreaticoduodenal lymph 
nodes are located between (he duodenum and 
pancreas and are associated with the pan 
creaticoduodenal artery Some of the lymph 
nodes may be found partly embedded in the 
pancreas Usually there are five to ten lymph 
nodes 0 5 to 1 5 cm in size Afferents ongin* 
ate from the duodenum, pancreas, stomach 
and omentum Efferents pass to the celiac 
lymph nodes or they go to the ciliac lymph 
trunk Some of the efferents may terminate 
in the hepatic lymph nodes 
Cliiac lymph nodes (Fig 45-8) The 
celiac |v mph nodes are situated near the ongin 
of the celiac artery Usually there are two to 
four lymph nodes, 0 3 to 4 0 cm in size, and 
they are often not clearly distinguishable 
from the splenic and gastnc lymph nodes 
Afferent lymph vessels come from the lungs, 
mediastinum, diaphragm, spleen, liver, 
adrenal glands, and from the splenic, hepatic 
and pancreaticoduodenal lymph nodes 
Efferents join the celiac lymph trunk 


CRANIAL MESENTERIC 
LYMPHOCENTER 

Cranial mesenteric lymph nodes The 
cranial mesenteric lymph nodes are located 
near the origin of the cranial meserttenc 
artery Sometimes they are difficult to dis 
tinguish from the pancreaticoduodenal or 
colic lymph nodes Afferents come from the 
jejunal and colic lymph nodes and from the 
colon and pancreas Efferents join the intes 
tinal or visceral lymph trunks 

Jejunal lymph nodes (Fig 45-8) The 
jejunal ly mph nodes arc located in great num 
ber in the mesentery of the jejunum They 
form two rows of lymph nodes on each side 
of the mesentery, separated by the jejuna! 
arteries and a layer of fatty connective tis 
sue Afferents come from the jejunum and 
ileum and efferents join and form the je 
junal lymph trunk which terminates in the 
intestinal lymph trunk Some efferents of the 
distally located jejunal lymph nodes pass to 
the ileocolic lymph nodes 

Ileocolic lymph nodes (Fig 45-8) 
The ileocolic lymph nodes are situated near 
the termination of the ileum into the cecum, 
and some of the lymph nodes are located in 
the ileocecal ligament These lymph nodes 
are often not clearly distinguishable from the 
jejunal and colic lymph nodes Afferent 
lymph vessels come from the cecum, ileum 
and jejunum and from the adjacent jejunal 
lymph nodes Efferents pass to the intestinal 
lymph trunk. 

Colic lymph nodes (Fig 45-8) The 
colic lymph nodes are associated with the 
right colic artery and its branches which sup- 



J5- PORCINE LYMPHATIC SYSTEM 


1357 


the spiral part of the colon They are ex 
led by separating the spiral colls of the 
Ion Usually there are up to 50 lymph nodes 
! to 9 0 cm in length Afferent lymph ves 
Is come from the colon, cecum and 
sionally, also from the pancreaticoduodena 
mph nodes Efferents form the colic lympn 
unk winch joins the jejunal trunk to tor 
ie intestinal lymph trunk Sometimes 
olic trunk is not present, and instead tner 
xe several larger lymph vessels 

:audai mesenteric 

LYMPHOCENTER 

Caudal mesenteric limph nodes (Fig 45- 
&) The caudal mesenteric l>mph nodes are 
located along the descending colon to tne 
pentoneal reflection caudally Some of tne 
lymph nodes may not be clearly distinguish 
a ble from the cranial mesentenc 
nodes cramally, and caudally it may be dil 
ficult to differentiate them from the ano 
metal lymph nodes situated retropentonealiy 
the rectum Usually there are seven to 
u lymph nodes 0 2 to 1 2 cm m size Alter 
ents arnve from the descending colon and 
P a ncreas and, occasionally, also from the 
^ctal lymph nodes Efferents go to the 
et «al iliac and lumbar aortic lymph nodes 

lAR GE lymph trunks and ducts 

»I? AC,,eal trunks The tracheal trunks 
,.2“"“ 'he efferent lymph vessels of the 
thpv^ tetro Pharyngeal lymph node Usually 
ui;i orin one or two larger lymph trunks, 
alono .i? ln branch These trunks course 
ten^i e COTn mon carotid artery and the in 
of tt, ^ u ® u ^ ar v ein and receive the efferents 
Crania k middle and caudal deep cer 
tW nodes They may also receive 

v ka1 i v ete ? ts of the dorsal superficial cer 
in ij 1 "™ nodes shortly before terminating 
vein 'n^?y nmon jugular or brachiocephalic 
occat.J} left side the tracheal trunks may 
of tjJ MW empty also into the end portion 
Va daH(m* rac i c duct Furthermore, numerous 


VI Ihp J '-***Hiy «laU illlU L11C t 

Va riatu n0racxc duct Furthermore, numerous 
tru nksIl S of termination of the tracheal 

C?,\ common , t, 

atic i Uf L r*VMPHATic duct The right ljmpn- 
trorjt tn swine is referred to as a common 
tra ohenU Cas l 0nall y formed by the right 
8u Porfi f «?-,i Un ^ and the efferents of the dorsal 
may . Cervical lymph nodes This trunk 
1 taiBAn *° ^ Cm In length 
v mh ar t« | 1 ? UNKS (Figs 45-7 and 8) ^ 

5* nw?o? ks are formed by the efferents of 
° ne of nj lateral ihac lymph nodes 
8e trunks is usually found on the 


left dorsolateral side of the aorta and as it 
w dens gradually, it continues cramally as tlie 
rhvh Another lumbar trunk may be 
fo amd on l e ££rf side of the caudal vena 

left* ^rena^artery^Sometimes^Unrd lumbar 

StiaSSM 

or in the cistema chy i g \ -j^e , e j U nal 
confluence «c ef 

ferents of the J<y un ^ ,ymP 4 h 5 "8) deS The cohc 
Colic trunk ( g coramon efferents of 
trunk represents th oft however, 

the C0UC nnrSger lymph vessels present 
there are only JWS y fFlKS 45 _ 7 an d 8) 

Tl!e N Tn.Ishna, Trunk is the common trunk 

for the jejuni and coho trunks g) The 

Celiac TnuNK ! ed t0 as t he common 

celiac trunk is f efferents of the 

'r/me gasme hepanc and pancreauco 
duodenal lymph ‘".“.ctrunks are often absent 

Hepatic and gastnctrunK lymph 

U5 ”l y ,e a ave U .he heptui Sd gaslnc lymph 
nodes and join die celiac trunk ^ g) 

VISCEI1AL T J'^ N V e c g omm on trunk for the 
visceral ‘ ru "^ S l „ al trun ks It empties in 
celiac and ww* ™ a f the cisterna chyh 
the caudal Potion i t m The c|sterna 
CISTERNA CHYL1 t) , . confluence of the lum 
chyh is formed by th Jf represen ts a very 
bar and visceral greatly enlarged and 

irregularly shaped an* e,d mainly along the 

bulged lymph duct ^ ^ ^ abdomina i 

left dorsolateral 0 ^ ^ few cen tuneters 
aorta cxtendinK t0 the aor tic hiatus 

caudal to the renal artery e£timated on ^ 

The largest diam ,h e cistema may 

lymph C The cistema chyh 

vary from 0 through the diaphragm 

continues cramaW *" >• thoracic duct 

into the thorac.ccavitya ^ _ g ? and 8) 
THORACIC j ^ js the continuation of the 

The ‘h^^^nlafly into the thoracic cav 
cisterna chyli - right dorsal border 

-tv 11 CO “ r ?„ ,hc rc B .o i of thc ninth thorac.c 

0fth ^ h rcSons from the ninth to the 

'fi'Snnc vcitcbrae it is located lateral to 
It then turns gradually to the 
'he the thoracic cavity, located on the 

e aspect of the esophagus and the trachea 
ef j .U. right of the subclavian artery lb 1 , 
morarac duct finally terminates in the cranial 
vena cava or brachiocephahc vein 


1358 


PORCINE 


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Ran vie* L 1895 Structure de* ganglion* mesenterKjue* do pore 
Corapte rend. *eance« *oc fckd. 4 7 774 775 
Renerer F. and A. Lellevre 1911 Deveiopement de* Hematle* 
dan* le* Ganglion* lyraphatique* du pore Compte rend seance* 
aoc blot 74 12^0-1229 

Richter J 1902. Vergleiebende lmrr»uchungen fiber den mikn>- 
scoptschera Bau der Lymphdniten *on Pfenl Rind. Sch»*tn 
trod Hand. Atxh M i r Anal to 4C9-5J * 

Saar L 1 and R. Getty 1 962-63 Lymph node* of the head, neck And 
» boulder region of svetne Iona State University Vet 25 120- 
134 

Saar L L and R. Cetry 1964* The InterreDttonihip of the lymph 

ve**el connection* or the lymph node* of the head, reck, and 
shoulder region* of *»lne Ant J vet. Re* 25-618-636 
Saar L 1 and R. Cetty 1964b. The lymph vestels of the thoracic 
limb of islne Iowa State Lniverstty Vet 26 161 JC8 
Saar L I tad R. Cetty 19C4c The lymph node* and the lymph *e*- 
tel* of the abdominal wall pelvic wall and the pelvic limb of 
•wine Iowa Stale University Vet, 27 97 111 
Sabin. F P- 1902. On the origin of the lymphatic *y*tem from the 
duct in the pig Am J Anal, 1 367 389 
Sabin. F R- 1901 On the development of the superficial lymphatic* 
In the *Urt of the pi* Am. J An.it . 3 183-195 
Sabin. F R- 1905 The development of the lymphatic node* In the 
pit and their yelatlon to the lymph heart* Am J Anal . 4 335- 
389 

Spira. A. 1961 Die Lymphknotengruppen (Lymphocentra) bef dm 
Saugrmein llomologt*lerungiver»uch Inaug Di»»- Munchen. 
Tine C 1914 Late und W unclgebleie der Flrt»ch!ympfck«Oteo 
betm Rinde und Schwrtne Z t lleisch u. MUcfchyg 24 52V 
329 

Traotmann. A 1925 Die embryonale und pcaiembryorule Cat 
wicklung der Kardia drtiaemone In ilagen von Su* wrofa sowie 
d e Au.bOdung und phv*tologf*che Brdeutung de* lymphat 
iarhert fZrtobl»«0»cf>eri) Cewebe* to deraejbers. Ana t Ant. U> 
321-346. 

Traotmann A- 1926 Die Lymphknnten (Lymphonodi) von Su* 
*cro fa. ln»be*ondere deren Lymph *trom- F*rtmng»- und P->ck 
bilduogrvrrhiltnuse. Z f Arut Entw 78 733-755 
Zietrwhmann. 0 1958 Da* Lymph*y*tem. In Schdnberg, F and 
D Zleuxhmann. Die Auifuhning der tierirttnchm Flei*<V 
umenuchung. pp l-3a Bertln. Paul Parry 
Zictztcbnunn. O E. Ackrrknecht. and II Crau(rdt) 1943. Ellen 
berger and Baum ( Handbuch d*T 1 ergleichenden Anatomie der 
llaumiere 18th ed. Bertin. Springer V erlag 


SPLEEN 

by S Sisson 


The spleen is long and narrow (Fig. 45-12) 
Its long axis is nearly dorsoventral in di 
rection and is curved to conform to the left 
part of the greater curvature of the stomach 
The dorsal end lies under the vertebral ends 
of the last three ribs, it is related to the stom 
ach cramally, the left kidney caudally, and 
the left extremity of the pancreas medially 
The visceral surface has a longitudinal 
ridge on which the hilus is situated this 
divides the surface into nearly equal gastnc 
and intestinal areas which are in contact 
with the stomach and colon respectively The 
parietal surface is convex and is related to 
the left lateral and ventral wall of the abdo- 
men. The ventral end is smaller than the dor 
sal one it lies on the abdominal floor, usually 


In the umbilical region The spleen is attached 
so loosely to the stomach that it mav be re 
garded as being intercalated in the great 
omentum Jn large subjects it may reach a 
len gth of about 60 cm a width of about 8 to 1 0 
cm and a weight of about 350 gm Accessor) 
spleens may be found in the gastrosplenic 
ligament 


The Position of the spleen varies according to the fullness 
bHuV l f?J a£h and , Ut °T n The dorsal end varies 
'«««1 *nd has a wide range as might be 
SK* 11 £f y ^ lf !, COntact wl,h ,he kbe of the 
** £* nttaMjr J“« Cranial to the um 

bilietis As in other animal* the sire of the spleen is tx 
Va ^, b e ,^ Ever, , ln a >*«* adult it may be only a 
than 35 01,1 ^g. about e cm wide and weigh 
about 200 gm. * 



45 -PORCINE LYMPHATIC SYSTEM 


1359 


FIGURE 45-12 Spleen of pig, visceral surface 

1, Dorsal end 2 ventral end 3 stumps of splenic vessels 4 gastnc surface 5 
hllus with vessels 



THYMUS 

by W. G. Venzke 


The large thymus in young pigs extends 
caudally from the origin of the digastncus 
muscle, along the carotid arteries on either 
side of the neck to the thoracic inlet where 
the right and left sides appear to fuse The 
two thoracic portions occupy the precardial 
mediastinum Superficially the organ is re 
lated in its cranial portion to the omohyoideus 
muscle (Fig 40-10) 

In the fetus the thymus is grayish red, in 
older pigs, yellowish white to grayish red 
It is a lobular organ, soft in consistency In 


the five month old pig the thymus weighs 
about 80 gm and at nine months °f a 8 e about 
90 gm After one year the thymus involutes, 
leaving a framework of connective adipose 
tissue containing microscopic remnants of 
active tissue 

Vessels and nerves The blood supply 
arises from branches of the common carotid 
and internal thoracic arteries Afferent 
lymphatics are received h> the cervical, 
sternal and cranial mediastinal lymph nodes 
The nerve supply is vagosyrfl pathetic 


CHAPTER 


PORCINE 

NERVOUS SYSTEM 


CENTRAL NERVOUS SYSTEM 

by H.-D. Dellmann and R. C. McClure 


SPINAL CORD 

(Figs 46-1, 2 and 3) 

The cervical enlargement of the spinal cord 
of the pig is composed primarily of the 
seventh and eighth cervical spinal cord seg- 
ments and is located in the vertebral canals of 
the sixth and seventh cervical vertebrae The 
lumbar enlargement, although not so prom 
ment as in other species, is at the level of the 
sixth and seventh lumbar spinal cord seg 
ments, which are located in the vertebral 
canal of the sixth lumbar vertebra. The spinal 
cord ends caudally between the cranial edge 
of the second sacral vertebra and the middle 
of the third sacral vertebra. The cross section 
of the spinal cord is almost circular, except at 
the cervical and lumbar enlargements, where 
it is flattened dorsoventrally 
The tract or fiber systems of the spinal cord 
in the pig have been sparsely studied. It has 
been reported that the corticospinal tract 
reaches only to the first cervical segment A 
spinothalamic tract has been demonstrated, 
it is only a small part of the fiber systems con 
tabled m the ventrolateral funiculus of the 
spinal cord 
1360 


BRAIN 

Rhombencephalon 

MYEIENCEPH AVON 
(MEDUll A OBtONGATA) 

The medulla oblongata of the pig Is rela- 
tively wider than the medulla of the other 
domestic animals (Fig. 46-4) The trapezoid 
body is broad and thin and protrudes very 
little from the ventral surface The facial 
tubercles are very slight elevations caudal to 
the trapezoid body 

The pyramids are visible on the ventral sur- 
face on either side of the midline but do not 
protrude on the surface. The olivary nuclei 
produce a prominence on the ventral aspect 
at their points of ongin 

The dorsal surface of the medulla is almost 
completely covered by the broad cerebellum. 
The tubercle of the gracile nucleus is very 
small, and the tubercle of the cuneate nucleus 
quite large The dorsal lateral sulcus of the 
spinal cord is continued rostrally by a prom- 
inent groove lateral to the cuneate fascicle 
— 1 tubercle 



1361 


46- PORCINE NERVOUS SYSTEM 



The rhomboid fossa presents prominent 
areas over the hypoglossal and vagal nuclei, 
and the vestibular area is slightly raised, as is 
the locus ceruleus laterally. The dorsal 
cochlear nucleus or acoustic tubercle is 
rather poorly developed. The medial eminence 
in the rostral part of the rhomboid fossa is a 
slightly elevated area. 

The lateral recesses which extend from the 
fourth ventricle are very well developed and 
may even point cau dally and ventrally. 

The microscopic anatomy of the medulla oblongata is, 
in general, described in Chapter 13 For further informa- 
tion on the cytoarchitecture of the major nuclei in the 
medulla oblongata of the domestic pig. see the literature 
references 


Metencephalon 


Pons 

In the pig the transverse fibers of the pons 
are considerably flatter and less prominent on 
the ventral surface of the brainstem than in 
the other domestic animals. It reaches its 
greatest width in the midline and decreases 
continuously in width toward the dorsolateral 
parts, where it enters the cerebellar hemi- 
spheres as the middle cerebellar peduncles. 
The basilar sulcus of the pons is a very shallow 
groove on the ventral midline. The rostral edge 
of the pons is very thick, rounded and set off 
from the cerebral crura by the prepontine sul- 
cus; the caudal edge is rather flat, barely evi- 
dent and separated from the trapezoid body 
and the pyramids by a very shallow sulcus. 

The reader will find general information on the micro- 
scopic anatomy of the pons in Chapter 13, which is for the 
most part applicable to the pig 


Cerebellum 

The pig cerebellum is a very wide struc- 
ture with enormous lateral hemispheres 
which largely extend beyond the lateral edges 
of the medulla oblongata (Fig. 46-4). It is 
topographically very closely related to the 
cerebellar surface of the cerebral hemi- 
sphere, from which it is separated by the 
membranous tentorium cerebelli, and to the 
lamina tecti which indent the organ at the 
level of the vermis and the medial part of the 
hemispheres. The entire rostral surface of the 


FIGURE 46-1. Cervical and thoracic parts of spi- 
nal cord. 

1. Wing of atlas, first cervical vertebra; 2. sixth cervical 
spinal n.; 3. first thoracic rib. 4. twelfth thoracic spinal n. 





46— PORCINE NERVOU^ SYSTEM 


1363 


FIGURE 46-4. Porcine brain, ventral 
view. 

1, Intermediate olfactory tract; 2, diagonal 
gyms; 3, proximal hypophysis, 4, distal part 
of adenohypophysis; 5, oculomotor n.; 6, ab- 
ducent n.; 7, glossopharyngeal n.; 8, vagus 
n.; b, caudal rootlets ot vagus t» ; Y<\ spVna\ 
root of accessory n.; 11. olfactory bulb; 12, 
lateral rhinal sulcus, rostral part; 13, medial 
olfactory tract; 14, lateral olfactory tract; 15, 
optic chiasm; 16, piriform lobe, caudal part; 
17, intercrural fossa; 18, trigeminal i'., 19, 
facial n.; 20, vestibulocochlear n.; 21, pyra- 
mid; 22, hypoglossal n. 



cerebellum in the pig is subdivided into folia 
or leaves which are continuous from the 
vermis to the hemispheres in the depth of the 
very shallow depressions or sulci bordering 
the vermis. Parts of the dorsal and the caudal 
surfaces of the cerebellum are much tnore ir- 
regular and are subdivided into lobes and 
lobules. 

The primary fissure is a deep fissure which 
divides the cerebellum into rostral and caudal 
halves which are clearly recognizable be- 
cause of the regular arrangement of the 
leaves in the rostral part and the irregular ar- 
rangement in the caudal part. The lingula, 
central lobule and culmen make up the ros- 
tral part of the vermis; the two former ones 
arc in contact with the rostral medullary 
velum and the lamina tecti of the mesen- 
cephalon. The culmen is followed caudally 
by the declive, the very irregular and often 
very prominent folium and tuber vermis, and 
the pyram'is which continues into thehnguia 
and its most rostral part, the nodulus. The lat- 
ter two structures are related to the caudal 
medullary velum, the choroid plexus of the 
fourth ventricle, and the caudal cerebellar 
peduncles. 

The cerebellar peduncles are easily dis- 
tinguishable from one another. The caudal 
cerebellar peduncles (restiform bodies) are 
not so well marked from the rest of the 


medulla as in the other domestic animals. 
The middle cerebellar peduncles are situated 
lateral to the indentation formed by the cau- 
dal and rostral cerebellar peduncles; they are 
oval in shape and can be followed a short dis- 
tance before they enter the cerebellar hemi- 
spheres to split into the medullary lamellae. 
The rostral cerebellar peduncles to which the 
rostral medullary velum is attached are 
relatively short, round and thick and disappear 
in the mesencephalon ventral to the caudal 
colliculi. 

For a description of the general microscopic anatomy and 
fiber connections of the cerebellum see Chapter 13 and the 
literature references 


• Mesencephalon 

Removal of the cerebellum and part of the 
occipital poles of the cerebral hemispheres 
exposes the tectum or the dorsal part of the 
midbrain. The cerebral crura are ^ visible on 
the ventral surface, whereas the middle part, 
the tegmentum, reaches the ventral surface 
of the brain only in the depth of the inter- 
crural fossa. The caudal colliculi of thclamina 
tecti are extremely well developed and are 
larger than the rostral colliculi. They are 
slightly grayish in color, especially their 
caudolateral point, whereas the rest of the 



PORCINE 


13G4 

caudal colliculi is considerably lighter in 
color, especially if compared with the rostral 
colliculi They are topographically related to 
the rostral cerebellar peduncles, the cere 
bellar hemispheres and the vermis which is 
located in the midhne just between the 
prominent tubercles Over the midhne the 
caudal colliculi are connected by a rather 
large, flat fiber strand, which forms a support 
for the caudal portion of the rostral colliculi 
A well pronounced sulcus forms the limit be 
tween the rostral medullary velum and the 
rostral cerebellar peduncles and continues 
into the <£prepontme sulcus and the sulcus 
limitans of the lemniscal tngone, a deep fur 
row forms the line of demarcation between 
the caudal colliculi their peduncles and the 
medial geniculate body, respectively 
The rostral colliculi are almost heml 
spherical, when seen from above they are 
triangular in shape, with their sides directed 
rostrolaterally, caudolaterally and medially 
Separated from each other by a deep groove, 
the rostral colliculi are set off from the adja- 
cent caudal colliculi and the lateral geniculate 
bodies by a continuous groove which becomes 
very shallow toward the rostromedlal part of 
the colliculi close to the midline where the 
brachium of the rostral colliculus emerges 
beneath that colliculus 
The lemniscal tngone is situated ventral to 
the brachium of the caudal colliculus and is 
separated by shallow sulci from the just 
mentioned brachium, the rostral cerebellar 
peduncle and the cerebral crura and by the 
deep 4>preponhne sulcus toward the pons The 
transverse crural tract emerges as a round, 
small fiber tract at the junction of the ^iatejal 
mesencephalic sulcus and the sulcus be 
tween the rostral cerebellar peduncle and the 
lemniscal trigone The transverse crural 
tract may become invisible on the ventral sur 
face of the cerebral crura or may be a very flat, 
barely visible tract which can be followed for 
only a very short distance and rarely to the 
sulcus of the oculomotor nerve 
The cerebral crura emerge rostral to the 
pons as two broad, thick fiber bundles which 
diverge considerably toward the diencephalon 
and the optic tracts rostrally They are sepa 
v rated by the intercrural sulcus which starts 
slightly rostral to the pons the space be 
tween it and the pons being occupied by a 
small gray elevation, the intercrural nucleus 
The sulcus widens rostrally into the inter 
crural fossa (Fig 46-4) The crura in the pig 
are easily separated into lateral and medial 
portions The lateral portion Is by far the 
larger and is convex in the ventrodorsal di 
reclion and separated from the medial por- 
tion by a shallow furrow, the medial portion is 
narrower than the lateral and very flat, or in 
some instances even concave, and has a 


darker gray color, which is apparently due to 
the fact that the ventral white layer is much 
thinner The transverse crural tract, or a fur- 
row which is located at its level or slightly 
caudal to it, divides the crura into a rather 
convex, even tubercle like rostral portion and 
slightly convex caudal portion 

For microscopic anatomy general organization and 
function of the mldbraln *ec Chapter 13 


Prosencephalon 


DIENCEPHAtON 

The part of the dienccphalon appearing on 
the ventral surface of the brain, between the 
cerebral crura, Is called the tuber cmereum 
Its most caudal part, the mamillary body, is a 
large, white, almost hemispherical and very 
prominent unpaired tubercle The middle and 
rostral parts of the tuber cinereum are gray 
in color and much wider than the mamillary 
body and convex In all directions The supra- 
optic commissure appears as small white 
fiber bands which parallel the optic tracts 
caudomedially across the cerebral crura. They 
pass dorsolaterally and caudally and appear to 
end In the lateral geniculate body, some 
fibers, however, may terminate In the medial 
geniculate body 

The third ventricle separates the dien- 
cephalon into two symmetrical parts The dor- 
sal part of the third ventricle Is much wider in 
the pig than in all other animals previously 
described In the mcdiolateral and rostro- 
caudal directions the dorsal part of the third 
ventricle is slightly convex and bordered 
laterally by the stria habenularis thalami 
Macroscopically the stria habenulans thalami 
begins at about the level of the opening of the 
third ventncle into the two lateral ventricles 
It is a narrow white band which widens 
caudally to form the very thick habenula, 
which is connected by the habenular commis 
sure to the habenula of the opposite side 
Immediately rostral to the beginning of the 
habenulae is a thickening which is due to the 
presence of the habenular nucleus The 
pineal body is a rather small, cone shaped 
organ which lies dorsal to and between the 
two rostral colliculi of the mesencephalon 

The dorsomedtal and dorsolateral surfaces 
of the diencephalon, situated laterally from 
the stna habenulans thalami, are rather ir 
regular The dorsomedia] surface of the 
thalamus is charactenzed by a small rostral 
tubercle and pulvmar, followed laterally and 
caudally by the lateral geniculate body 
whose surface is entirely covered by the fibers 
of the optic tract The medial geniculate body, 
situated almost on the caudolateral surface of 



46— PORCINE NERVOUS SYSTEM 


1365 


the diencephalon, is extremely well de- 
veloped. It is a grayish round structure sepa- 
rated by rather deep grooves from the sur- 
rounding structures, the optic tract dorso- 
laterally, the cerebral crura ventromcdially, 
the brachium of the caudal colliculus caudal- 
ly and the rostral colliculus dorsomedially. 

The point of fusion of the two halves of 
the diencephalon is the interthalamic ad- 
hesion and the ventral part of the hypo- 
thalamus rostrally and caudally to the attach- 
ment of the hypophysis. The rostral limit of 
the diencephalon is indicated grossly by the 
lamina ternnnahs grisea, a thin plate which 
lines the third ventricle rostrally; caudally 
the diencephalon is continuous with the 
mesencephalon. 

For microscopic anatomy and function, reference is 
made to the descriptions in Chapter 13 and to the special 
literature references giving information on some special 
features in the pig 


TEIENCEPHAION 

The variations in the form of the tel- 
encephalon are influenced much more by 
breed in the pig than in the horse and rumi- 
nants. The pig telencephalon has a charac- 
teristic appearance, particularly that part of 
the telencephalon which is situated ventral to 


the rostral part of the lateral rhinal sulcus and 
the caudal part of the piriform lobe which face 
laterally rather than ventrally (Fig. 46-4). 
Therefore portions of the telencephalon, which 
in other species were definitely oriented 
ventrally, are oriented laterally. This holds 
true for the lateral olfactory tract as well as 
for the entire rostral perforated substance 
(or sometimes only its most lateral part). 

The hemispheres increase in height from 
rostral to caudal, their dorsal circumference 
describing a regular curve. The frontal 
portion of the brain is considerably narrower 
than the temporal portion. The caudal part of 
the piriform lobe and the temporal lobe and 
the occipital pole are almost egg-shaped. 

Where the two plane medial surfaces of the 
hemispheres face each other they are sepa- 
rated by the longitudinal fissure (Fig. 46-5). 
The cerebellar surface is very flat (Fig. 46-6), 
barely indented by the insignificant rostral 
part of the cerebellar vermis. (For the de- 
scription of the basal surface of the telen- 
cephalon, see Chapter 13.) 

The floor of the rostral portion of the 
central part of the lateral ventncle is formed 
by the caudate nucleus, one of the basal 
nuclei of the hemispheres. Its rather large 
head begins in the rostral part of the lateral 
ventricle; therefore, part of the head lies be- 
neath the ventricle. The lateral edge of the 


FIGURE 46-5. Porcine brain, dorsal 
view. 

1, Endomarginal sulcus, 2, eclomarginal 
sulcus, 3, marginal sulcus, 4, marginal 
gyrus, 5, 4 t cruciate gyrus, 6, <J coronal 
gyms; 7, <fc sigmoid gyrus, 8, eclomarglnal 
gyrus, 9. caudal suprasylvian sulcus, JO, 
middle suprasylvian sulcus, 1 1, connection 
between the rostral suprasylvian sulcus and 
coronal sulcus, 12. coronal sulcus, 13, cru- 
ciate sulcus, 14, rostral suprasylvian sulcus 



136G 


PORCINE 



8 9 10 11 12 

FIGURE 46-6. Poreine brain; lateral view 


1, Pretylvian tulcus; 2, diagonal tulcuc; 3, middle «uprarylvian sulcus; 4. sylvian gyros, 5. ectosylrlan sulcus; 6. ec- 
losylvian gyrus; 7, eclomarginal gyrus; B. coronal sulcus. 9. lateral rhinal sulcus, rostral part; 10. sylvian fissure. 1 1. lat- 
eral rhinal sulcus, caudal part. 12, caudal suprasylvian sulcus. 


dorsal convex surface of the caudate nucleus 
follows the border between the dorsal and 
lateral walls of the lateral ventricle just 
beneath the subcallosal fascicle; the ventro- 
medial edge of the dorsal surface is parallel 
to the stria terminalis. At the level of a frontal 
plane through the rostral commissure the 
width of the caudate nucleus decreases con- 
siderably to form the thin tail. This tail ends 
macroscopically after a lateTOventral curving, 
with an increase In thickness almost at the 
level of a frontal plane through the rostral 
edge of the lateral geniculate body. The lateral 
surface of the caudate nucleus is almost flat, 
in some instances somewhat concave, and 
faces the internal capsule. 

The putamen begins caudal and lateral to 
the beginning of the head of the caudate 
nucleus. The two structures at this level as 
well as the nucleus accumbens septi on its 
medial side cannot be separated. The putamen 
increases in height dorsally and ventrally, but 
is always somewhat smaller than the caudate 
nucleus. The lateral surface of the putamen 
is convex. The medial surface toward the 
internal capsule is concave; its ventral edge 
is smooth, its dorsal one very irregular. Both 
nuclei are separated by the fiber masses of 
the internal capsule, through which they are 
connected by numerous gray bridges. 

Macroscopically it is impossible to identify 
the pallidum; microscopically the nerve cells 


of the pallidum are located between the fibers 
of the internal capsule, ventromedial to the 
putamen. 

The projection fibers of the internal cap- 
sule are readily identifiable as a large fiber 
mass between the caudate nucleus and puta- 
men. The parts of the internal capsule which 
are located at this level are referred to as the 
rostral limb and the genu. The caudal limb is 
found between the diencephalon and puta- 
men ventrally. The Internal capsule spreads 
its fibers into the hemispheres as the corona 
radiata. 

The claustrum is an elongated and almost 
quadrangular, irregular layer of gray sub- 
stance which, because of its thinness, can be 
dissected only with difficulty. The claustrum 
lies in the depth of the insular region and be- 
comes apparent only after removal of the 
short insular gyri and their association fibers 
as well as of the extreme capsule, a very thin 
fiber layer 

Grossly the amygdaloid body which makes 
up the protuberance of the caudal part of the 
piriform lobe may be divided into at least two 
nuclei which, on the basis of their cytology 
and the fiber divisions, may be microscop- 
ically subdivided further. The entire complex 
is almond-shaped; one extremity is situated 
In the caudal part of the piriform lobe and the 
other extremity lies against the lumen of the 
lateral ventricle. The topographical relation- 


46 — rOUCINE NERVOUS SYSTEM 1367 


ships are the same as described in the general 
section 

In contrast to all the species described 
previously, the sylvian fissure on the lateral 
side of the hemisphere in the pig is not the 
most prominent fissure, but resembles all the 
other fissures Originating from the lateral 
rhinal sulcus at the level of the lateral fossa 
jn the insular region, it is directed dorso- 
caudolaterally and in some breeds consists of 
only one single branch, the middle one 
(<£>ramus acumints') In other breeds this 
branch im> be a strictly Vertical one, with 
smaller sulci given off m caudal and rostral 
directions which correspond to the sulci 
described for the horse and the ruminants 
The rostral branch may be continuous with 
the diagonal sulcus 

Regardless of its topography, the sylvian 
fissure is surrounded by the rostral, middle 
and caudal suprasylvian sulci, which form 
an irregular arch around it Caudally the 
middle suprasylvian sulcus continues into 
the caudal suprasylvian sulcus, which runs 
slightly rostral and almost joins the caudal 
part of the lateral rhinal sulcus Rostrally the 
rostral suprasylvian sulcus runs almost 
parallel to the rostral part of the rhinal sulcus, 
giving off small perpendicular sulci, and its 
most rostral end is vertical At the limit of the 
caudal and middle thirds of the hemisphere, 
the middle suprasylvian sulcus gives off a 
branch which runs mediorostrally and which 
establishes a communication with the cru 
ciate (central) and the postcruciate (post 
central) sulci as well as the coronal sulcus 
The coronal sulcus, which is practically the 
rostral continuation of this branch of the mid 
die suprasylvian sulcus, runs parallel to the 
longitudinal fissure and deviates laterally 
somewhat in its most rostral part 
The presylvian sulcus has a topography 
similar to the one found in ruminants It 
originates from the rostral part of the lateral 
rhinal sulcus in a rostrodorsomedial direction 
and ends medial to the rostral end of the 
coronal sulcus Ventrolateral to it, partly 
covered by the olfactory bulbs, lies the very 
poorly developed prorean sulcus The area be- 
tween the rostral part of the rostral supra 
sylvian sulcus and the coronal sulcus con 
tarns the sagittally oriented diagonal sulcus 
This sometimes communicates with either 
the rostral part of the rostral suprasylvian 
sulcus or the rostral part of the lateral rhinal 
sulcus or even, if present, with the rostral 
branch of the sylvian fissure The area be 
tween the communicating branch between 
the suprasylvian sulcus and the postcruciate 
sulcus and the caudal part of the suprasylvian 
fissure and the longitudinal fissure is divided 
into two unequal parts by the marginal sulcus 
The marginal sulcus is situated between 


the internal and the middle third of this area 
and runs over its entire length The medial 
part, between the marginal sulcus and the 
(j>calIo so marginal sulcus on the medial aur 
face of the brain, is again divided by the endo 
marginal sulcus, which is cither an indepen- 
dent short sulcus or communicates with the 
marginal sulcus The cctomarginal sulcus is 
found almost equidistant between the supra- 
sylvian sulcus and the marginal sulcus 
It is a relatively short sulqus which sub- 
divides only the caudal part of the territory 
between the two mentioned sulci or is con- 
tinued rostrally b> some small fragments of 
sulci On the medial surface of the hemi- 
spheres the arrangement of the sulci is almost 
similar to that found in ruminants 
The callosomarginal sulcus is an inter- 
rupted sulcus situated an equal distance be- 
tween the dorsal edge of the hemisphere and 
the corpus callosum in the caudal part of the 
medial surface of the hemisphere, and in the 
immediate neighborhood of the dorsomcdial 
edge of the hemisphere in its rostral part 
The caudal part of the callosomarginal sulcus 
is often referred to as the splcnial sulcus, it 
communicates with the continuation of the 
caudal part of the lateral rhinal sulcus on the 
cerebellar surface of the hemisphere and is 
often referred to as the temporo-occipital 
sulcus Rostrally it continues into the cruciate 
sulcus on the dorsolateral surface of the 
hemisphere In the rostral part of the medial 
surface of the hemisphere the callosomargmal 
sulcus may be referred to as the genual sul- 
cus This sulcus is sometimes accompanied 
by two more or less parallel sulci, one toward 
the periphery, the ^ectogenual sulcus, and 
the other one toward the corpus callosum, 
the «J>endogenual sulcus From the previous 
description it becomes obvious that, at least 
for didactic purposes, the lateral surface of 
the hemisphere should again be subdivided 
into the sylvian and ectosylvian convolutions, 
although the somewhat different topography 
of the caudal part of the lateral rhinal sulcus 
makes such a subdivision almost impossible 
Thus, the sylvian convolution would be 
limited in the periphery by the ectosylvian 
sulcus, the middle suprasylvian sulcus, the 
coronal sulcus and the presylvian sulcus, 
the ectosylvian convolution would be limited 
in the periphery by the caudal, rostral and 
middle suprasylvian sulci, the communi 
eating branch between the middle supra 
sylvian and the coronal sulcus, and the 
coronal sulcus, where the sylvian and the 
ectosylvian gyri blend 
Variations occur m the operculization of 
the insula In some breeds it is very pro- 
nounced and the insula totally hidden In 
others the insula appears clearly in the lateral 
surface of the cerebral hemisphere In the 



1368 


PORCINE 


case of total opercuhzation, the gyri breves 
seem to be much better developed than when 
tbe insula is visible, thus forming a rather 
uniform area. 

The dorsomedial gray matter of the cerebral 
hemisphere is limited by the cailosomarginal 
sulcus medially, the caudal and middle supra 
sylvian, coronal and presylvian sulci laterally 
It is divided into the marginal and the ecto- 
marginal gyn by the marginal sulcus 
The ectomarginal gyrus is very well de- 
veloped, occupying the lateral two-thirds of 
the entire caudal peripheral territory It is 
divided into two unequal parts by the ecto- 
marginal sulcus 

In Us caudal part the marginal gyrus is 
rather narrow Rostrally it continues into the 
sigmoid or cruciate gyrus and the latter’s 
rostral continuation, the prorean gyrus The 
marginal gyrus is interrupted by the cruciate 
and postcruciate sulci and their communi 
cations with the coronal and middle supra 
sylvian sulcL As in ungulates, the entire area 
is markedly depressed as compared to the sur 
rounding gyn. 

Besides the rather irregular gyn in the most 
rostral part of the medial surface of the hemi 
sphere, which bear the same names as the 
adjacent sulci, one finds in the caudal part 
the parahippocampal gyrus, the callosal 
gyrus, the tubercle of the dentate gyrus and 
the fasciolar gyrus and the angular gyrus, 
which surround the corpus callosum and 
blend into the precommissural area. 

Rostrally the rhmencephalon begins with 
the olfactory bulbs-two well developed fiat 
oval structures which are closely related to 
the frontal pole of the hemispheres In the pig 
not only the ventral part of the olfactory lobes 
but also part of the dorsal surface and the 
lateral edges receive the fila olfactona and are 
thus rough surfaced, therefore, onty that part 
of the dorsal surface which is adjacent to the 
frontal pole of the hemisphere has a smooth 
surface Because of the caudal elongation of 
the olfactory bulb, there is practically no 
olfactory peduncle, however, the two olfactory 
tracts are clearly recognizable 

The lateral olfactory tract originates from 
the dorsal and lateral surfaces of the ol 
factory bulb, it is a rather wide, flat fiber band, 
not very circumscribed, which becomes a 
well-defined tract lateral to the rostral part of 
the piriform lobe (area olfactona) This tract 
can be clearly followed to the lateral fossa. 
The well -dev eloped olfactory tubercle lies 
medial to the lateral olfactory tract 

The medial olfactory tract Is represented 
by a gray elevation which is separated from 
the rostral part of the piriform lobe (olfactory 
triangle) and the olfactory area by a shallow 
rostral ^parolfactory sulcus This sulcus 
disappears in the Jnterhemisphenc fissure 
and terminates in the precommissural area. 


Frequently the intermediate olfactory tract 
is clearly recogmzable as an extremely short 
flat fiber tract which disappears at the level 
of the rostral part of the piriform lobe 
(olfactory triangle) 

The rostral part of the piriform lobe or the 
olfactory area is a triangular area with an 
irregular convex surface between Broca’s 
diagonal bands and the olfactory tracts, it is 
pierced by numerous holes for the passage of 
blood vessels and is often referred to as the 
rostral perforate substance 
These bands appear laterally at the point 
where the lateral olfactory tract disappears 
m the caudal part of the piriform lobe, turn 
around the ventromedial edge of the hemi 
sphere and terminate in the precommissural 
area. 

Cau dally the paleopallium is continued by 
the caudal part of the piriform lobe This part 
of the lobe is extremely well developed in 
swine It is a very wide, oval, almost hemi- 
spherical structure which is lined laterally by 
the caudal part of tbe lateral rhinal sulcus 
The caudal part of the piriform lobe is divided 
by a sagittal sulcus into several gyri. 

The hippocampus is shaped like a ram’s 
horn, its ventricular surface is invaginated 
into the lateral ventricle and is convex in all 
directions The hippocampus forms part of 
the bottom of the lateral ventricle and be- 
gins approximately at the level where the 
body of the caudate nucleus blends into the 
tail, it surrounds the thalamus and terminates 
in the caudal part of the piriform lobe, with 
its end being slightly more rostral than its 
beginning. The ventricular surface of the hip- 
pocampus has a striated appearance owing to 
the presence of numerous fibers, which form 
the alveus At the rostral edge of the hippo- 
campus they form the hippocampal fimbria. 
The fimbria continues rostrally into the fornix 
and forms the hippocampal commissure at 
the rostromedial end of the hippocampus 
Ventrally a rather shallow sulcus, the hippo- 
campal sulcus, separates the parahippocampal 
gyms and the lateral dentate gyms, the latter 
being associated with the fimbna. 

The parahippocampal gyms is connected 
with the neocortex by small transitional gyri 
and ends dorsomedially near the tubercle of 
the dentate gyms The tubercle of the dentate 
gyms is adjacent to another small gyms of 
th^ paleopallium, the fasciolar gyms, which 
continues into the indusium griseum on the 
dorsal surface of the corpus callosum. 

The dentate gyms begins with a slight 
thickening at its rostrolateral end. In its mid 
die and caudal parts it becomes a rather nar 
row gray band, which generally does not 
possess the characteristic indentations re- 
sponsible for the name of this gyms It ends 
dorsomedially with a tubercle, the tubercle of 
the dentate gyms 



46 -PORCINE NERVOUS SYSTEM 


The largest commissural system of the 
cerebral hemispheres is the corpus callosum 
On a midsagittal section through the brain 
it appears as a thick fiber plate with slightly 
thickened ends, the splemum and the genu of 
the corpus callosum Its dorsal surface is 
slightly convex or fiat and continues into the 
two hemispheres, where it forms the radia- 
tion of the corpus callosum, the fiber bundles 
which connect corresponding cortical areas 
of the hemispheres 

The two olfactory areas and the amygda- 
loid complexes are connected by the rostral 
commissure whose topography has been de- 
scribed in detail in Chapter 13 As the ar- 
rangement is similar m the pig, the reader is 
referred to that section. 

The area between fornix and corpus cal- 
losum, and the precommissural area and 
corpus callosum, respectively, is filled by the 
telencephalic septum Between the fornix 
and the corpus callosum it is developed only 
m Its rostral part, rostral to the fusion of the 
fornix and corpus callosum The telencephalic 
septum consists of two very thin laminae 
which are separated by the cavity of the tel 
encephalic septum They are related to a well 
developed nucleus, the nucleus accumbens 
septi, in the ventral part of the septum which, 
m turn, is closely related to the head of the 
caudate nucleus, from which, ventrally, it is 
not separable 

The hippocampus and mamillary bodies are 
connected by the fornix Originating from the 
alveus, the fibers form the hippocampal 
fimbria at the rostrolateral edge of the hippo- 
campus The two fimbriae fuse in the midline 
to form the hippocampal commissure and 
continue rostrally as the two crura to form the 
body of the fornix. From the body extend the 
two columns of the fornix which terminate 
in the mamillary bodies The topographical 
relations of the fornix were described in the 
horse section and are valid for swine as well 
Besides the association fiber bundles which 
connect adjacent gyn with more distant ones, 
the cingulum and the subcallosal bundles are 
the only bundles which are easily demon 
strable macroscopically The cingulum ex- 
tends between the precommissural area and 


1369 

the amygdaloid complex, dorsally paralleling 
the corpus callosum 

The subcallosal bundle or dorsal occipito- 
frontal bundle is situated at the dorsolateral 
edge of the lateral ventricle, just beneath the 
radiation of the corpus callosum At the level 
of the head and the body of the caudate 
nucleus, it is a very thin fiber bundle whose 
fibers spread out considerably m the dorso- 
caudal wall of the lateral ventricle and ter- 
minate In the occipital lobe * 

The inferior longitudinal fascicle (ventral 
fronto-occipital bundle) consists of a few 
fibers which are demonstrable ventromedially 
to the insular area. Passing laterally over the 
amygdaloid complex, they connect frontal 
and occipital lobes 

For the description of the long and short 
projection systems, see Chapter 13 


MENINGES 

The meninges in the pig are similar to the 
description in the general section and only the 
details applicable to the pig will be given in 
this section 


DURA MATER 

The falx cerebn in the pig is narrow and 
does not extend ventrally to the corpus cal- 
losum, but only about one-half the distance 
from the dorsal edge of the cerebral hemi- 
spheres to the corpus callosum 

The spinal dura mater filum is usually at- 
tached caudally to the body of the sixth caudal 
vertebra and occasionally to the fifth or 
seventh caudal vertebra. 


ARACHNOID AND PIA MATER 

The arachnoid and pia mater present no 
special features The subarachnoid cavity ex- 
tends caudally to the level of the last sacral 
vertebra and is quite small from the level of 
the second sacral vertebrae to its caudal ter- 
mination 



1370 


PORCINE 


PERIPHERAL NERVOUS SYSTEM 


CRANlAl NERVES* 

by H P Godmho and R Geliy 

Olfactory Nerves (1) 

The olfactory nerves are distributed to the 
mucous membrane of the olfactory region of 
the nasal cavity This region comprises the 
caudal portion of the dorsal nasal concha the 
ethmoidal conchae and the corresponding 
area of the nasal septum The nerve fibers 
originate from the central processes of the 
olfactory cells and are joined to one another 
forming bundles which pierce the cribriform 
plate of the ethmoid bone and terminate in 
the olfactory bulb 

Terminal nerves The terminal nerves 
of pig fetuses are described by Johnston 
(1913 1914) as consisting of a ganglionated 
nerve whose root enters the telencephalon 
caudal to the olfactory bulb This nerve 
exists in addition to the vomeronasal nerve 
and is chiefly distributed to the vomeronasal 
organ. 


Optic Nerve (II) 

The optic nerve grossly arises from the optic 
chiasm and after traversing the optic canal 
reaches the orbital cavity Here the nerve is 
surrounded throughout its extent by the 
cranial meninges It runs at first dorso- 
laterally then bends slightly dorsorostrally 
to reach the eyebalL The optic nerve relates 
to the retractor bulbi muscle and on its dor 
sal aspect is also related to the ciliary nerves 


Oculomotor Nerve (111) 

The oculomotor nerve (Fig. 46-7) is the 
largest of the nerves to the extrinsic muscles 
of the eye It emerges on the ventral side of 
the cerebral crus at the border of the inter 
crural fossa. Coursing rostiad and laterad 
it perforates the dura mater of the cavernous 
sinus It then leaves the cranial cavity through 
the foramen orbitorotundum in company 
with the maxillary ophthalmic abducent and 
trochlear nerves At the orbital apex the oculo- 
motor nerve relates medially to the naso- 
ciliary nerve and divides into dorsal and 
ventral branches The dorsal branch is very 
short and Immediately penetrates the rectus 
dorsalis muscle Some of its fibers perforate 


•For details of ganglia and the course ol autonomies 
»ee the section on the autonomic system in Chapter 13 



A Nasal bone B frontal sinus C lacrimal foramina D 
zygomatic process cut E. ocular bulb F ethmoidal fossa 
G obliquus dorsalis H lacrimal gland I rectus dorsalis 
J canal for hypoglossal n. l motor root of trigeminal n. 
2 sensory root of trigeminal n. 3 mand bular n. 4 
trigeminal ganglion S maxillary n. 6 zygomaticofacial 
branch 7 zygomaticotemporal branch 8 lacrimal n. 9 
frontal n. (divides Into supratrochlear and supraorbital 
nn.) 10 nasociliary n. 11 ethmoidal n_ 12 infratrochiear 
n. 13 oculomotor n. 14 abducent n. 15 trochlear n. cot. 
(From Godmho and Getty 1968a.) 



46 -PORCINE NERVOUS SYSTEM 


1371 



FIGURE 46-8. Nerves of the deep lateral surface of the head of the pig (semischematic). 

A, brachiccepbalieus, B. stemocephabcus, C. mandibular gland, D parotid gland (ventral portion) E, zygomatic process 
of temporal bone (cut), F. facial a., G, maxillary a . H, pterygoideus lateralis, J, stylohyoideus, J, pterygoideus medialis, K, 
mandibular duct, L.orblculans oculi, M, obliquus ventralis, N, deep gland of third eyelid, O. buccal gland, P, buccinator, 
Q, depressor labil mandibulam, R, mylohyoideus, S, digastncus, T, levator labii maxillaris, U, camnus, V, depressor labii 
maxillaris, W, orbicularis ons, X, levator nasolabialis, Y, mentahs, 1, accessory n . 2, facial n , 3, internal auricular n. 
(cut), 4, caudal auricular n (cut), 5, dorsal buccal branch (cut), 6, cervical branch (cut), 7, ventral buccal branch, 8, 
stylohyoid branch, 9, branch of external carotid n , 10, hypoglossal n , 1 1, mandibular n , 12, auriculotemporal n , 13, mas 
seteric n , 14, deep temporal n , 15, branch of buccal n to temporalis, 16, buccal n , 17, lingual n , 18, branch to isthmus 
faucium, 19, mandibular alveolar n , 20, mylohyoid n , 21, communicating branch of 9 to 20, 22. lateral branch of 
mylohyoid n., 23, medial branch of mylohyoid n , 24, ventral buccal branch 25, mental nn , 26, dorsal buccal branch 
(cut), 27, frontal n , 28, lacrimal n , 29. zygomaticotemporal branch, 30, zygomaticofacial branch, 31, accessory zygoma- 
ticofacial branch, 32, communicating branch with oculomotor n , 33, ventral branch of oculomotor n , 34, maxillary n ; 
35, caudal maxillary alveolar branch, 36. external nasal branches, 37, internal nasal branches, 38. branches to upper lip, 
39, 40, muscular branches of dorsal buccal branch (From Godinho, 1966 ) 


the latter to innervate the levator palpebrae 
superioris. The ventral branch (Figs. 46-8, 
9 and 10) dips between the optic nerve and 
retractor bulbi muscle and courses along the 
ventrolateral surface of the optic nerve where 
it gives off short twigs to the internal surface 
of the recti mediahs and ventralis muscles. The 
ventral branch gives off the oculomotor root* 
to the ciliary ganglion, which is detached 
together with twigs to the rectus ventralis 
muscle. Lastly, the ventral branch passes 
rostrally on the lateral surface of the rectus 
lateralis muscle to end in the obliquus ven- 
trails. 


*Th« fiben connected with the ganglion are generally 
de»cribed ns Its root*. 


The ciliary ganglion (Fig. 46-10) is located 
on the ventrolateral surface of the optic nerve 
at its first curvature in the orbital cavity. It is 
connected to the ventral branch of the oculo- 
motor nerve by means of several radicles, the 
oculomotor root. The distance between the 
ganglion and the ventral branch of the oculo- 
motor nerve is variable. In some cases the 
ganglion is situated very close to that branch, 
whereas in others they are up to 5 mm apart. 
In 80 per cent of the cases an <f.accessory 
ciliary ganglion is present, and is situated on 
the dorsolateral surface of the optic nerve. It 
is smaller, 3 to 6 mm apart from the main gan- 
glion, and associated with the latter by 
means of one or two connecting twigs. The 



1372 


PORCINE 


ciliary and accessory ciliary ganglia give off 
two to three slender, Bhort ciliary nerves (Fig 
46-10) which course along the optic nerve to 
penetrate In the posterior part of the eyeball. 
The ciliary ganglion receives some fibers from 
a large branch originating from the maxillary 
nerve— the communicating branch with the 
oculomotor nerve -which, coursing dorsally, 
reaches the ventral branch of the oculomotor 
nerve and the ciliary ganglion (Fig. 46-10). 
Finally, the ciliary ganglion gives off the 
branch communicating with the nasociliary 
nerve which courses caudad on the ventral 
branch of the oculomotor nerve and at the 
level of the orbital apex leaves the latter to 
join the nasociliary nerve. 


Trochlear Nerve (IV) 

The trochlear nerve (Fig. 46-7) is a slender 
fiber bundle that emerges from the rostral 
cerebellar peduncle close to the caudal col- 


liculus it courses laterally and penetrates the 
tentorium cerebclli The nerve travels in the 
edge of the tentorium cerebclli, which, in 
some cases, docs not present a complete canal 
for the nerve In the tentorium cercbelll the 
nerve releases the meningeal branch which, 
after a recurrent course, disappears in the 
structure of the dura mater. The trochlear 
nerve leaves the cranial cavity through the 
upper portion of the foramen orbltorotundum. 
Coursing over the insertion of the rectus dor- 
salis and levator palpcbrae superioris, it 
reaches the dorsal surface of the caudal third 
of the obliquus dorsalis muscle. Here it divides 
into two or three branches which disappear 
grossly into the lateral border or dorsal sur- 
face of the latter muscle. 

Trigeminal Nerve (V) 

The trigeminal nerve emerges from the 
lateral aspect of the pons by means of two 
roots-the large sensory root and the small 



• - -i , a . . ... * .... 3, lacrimal n ; 9, communicating 

branch between 7 and 8. 10. zygomaticofacial branch. 11, accessory zygomaticofacial branch. 12. ventral branch of 
oculomotor n.; 13, communicating branch, with oculomotor n (From Godlnho and Getty. 1968a) 



46— PORCINE NERVOUS SYSTEM 


1373 



FIGURE 46-10, Nerves of the lateral surface of the orbital and pterygopalatine regions of the pig, deep 

view (semischematic.) 

A, Ocular bulb, B, lacrimal gland, C, obliquus dorsalis, cut, D, rectus lateralis, cut, E, rectus ventralis, F, obliquus 
ventralis: C, deep gland of third eyelid, H, retractor bulbi, 1, pterygopalatine ganglia, 2, n of the pterygoid canalr3, max- 
illary n , cut, 4, zygomaticofacial branch, cut, 5, abducent n , 6, ventral branch of oculomotor n , 7, communicating 
branch with oculomotor n , 8, ciliary ganglion, 9, short ciliary nn. (From Godinho and Getty, 1968a.) 


motor root (Fig. 46-7) The sensory root runs 
rostrad to reach the trigeminal ganglion 
(Fig. 46-7), which is placed lateral to the 
hypophyseal fossa and covers, in part, the 
foramen lacerum. The motor root passes 
under the ganglion to constitute part of the 
mandibular nerve. From the trigeminal gan- 
glion, most of the fibers course rostrad into 
the foramen orbitorotundum and give rise to 
the maxillary and ophthalmic nerves; how- 
ever, a portion of them joins the mandibular 
nerve, constituting the great part of its bulk. 
Other fibers, after a short recurrent course, 
dorsally penetrate the dura mater and con- 
stitute the meningeal branch. The trigeminal 
nerve gives off three nerves: 

Ophthalmic nerve. The ophthalmic nerve 
is the smallest division of the trigeminal 
nerve. It originates at the exit of the foramen 
orbitorotundum from a common trunk with 
the maxillary nerve. The ophthalmic nerve 
immediately divides into the following main 
branches: 

The lacrimal nerve, after a short course, 
divides into two or three branches as it 


ascends the orbit on the dorsal surface of the 
recti dorsalis and lateralis. The most lateral 
branch receives a communicating twig from 
the zygomaticotemporal branch. Usually the 
smaller branches penetrate the lacrimal gland, 
whereas the others reach the skin of the lateral 
portion of the upper lid and adjacent area, 
where they distribute. 

The frontal nerve emerges from the oph- 
thalmic in very close association with the 
lacrimal nerve. It travels rostrodorsally under 
the pen orbit and then, at the level of the peri- 
orbital ligament, perforates the latter to in- 
nervate the skin of the frontal region. The 
frontal nerve divides, at a level which varies 
from the orbital apex to the periorbital liga- 
ment, into supratrochlear and supraorbital 
nerves. The former is usually the smaller and 
is medially located, whereas the supraorbital 
represents the continuation of the frontal and 
is more laterally located. It also releases fibers 
to the obliquus dorsalis and rectus dorsalis 
muscles. 

The nasociliary nerve (Fig. 46-7) represents 
the continuation of the ophthalmic nerve in 




PORCINE 


1374 

the orbit It receives the communicating 
branch from the ciliary ganglion, passes be 
tween the rectus dorsalis and retractor bulbi 
muscles and gives off two or three slender 
long ciliary nerves The long ciliary nerves 
course over or m the structure of the retrac 
tor bulbi muscle and perforate the sclera near 
the attachment of the optic nerve The naso- 
ciliary nerve then divides Into two branches 
One is the ethmoidal nerve which, after 
passing between the levator palpebrae supen 
ons and the rectus mcdialis muscle leaves 
the orbital cavity through the ethmoidal fora 
men in company with the external ethmoidal 
artery Coursing on a bony sulcus of the dorsal 
part of the ethmoidal fossa, the ethmoidal 
nerve furnishes a meningeal branch and 
reaches the* medial side of the cnbnform 
plate The ethmoidal nerve leaves the eth 
moidal fossa through a small bony canal, 
traverses the cribriform plate and reaches the 
nasal cavity In the latter it courses rostrally 
on the dorsal nasal concha, sends off branches 
(internal nasal branches) to its mucosa (lateral 
nasal branch) and to the nasal septum (medial 
nasal branch) and terminates as the external 
nasal branch, which contributes to the in 
nervation of the nostril The other branch 
resulting from the division of the nasociliary 
nerve is the infratrochlcar none (Fig 46-7) 
This nerve runs dorsad on the medial surface 
of the rectus medialis muscle, passes ventral 
to the trochlea for the obliquus dorsalis muscle 
and then divides into two branches (palpebral 
branches) These branches, after crossing 
over the dorsal lacrimal canaliculus, reach 
the skin of the dorsal portion of the medial 
angle where they distribute 

The zygomaticotemporal branch arises 
from the lateral aspect of the ophthalmic 
nerve and receives contributions from the 
maxillary nerve to course on the lateral sur 
face of the rectus lateralis muscle After per 
forating the penorbit it reaches the skin of 
the temporal region where it distributes (Fig 
46-7) 

Maxillary nerve The maxillary nerve 
(Figs 46-9 and 10) is the largest division of 
the trigeminal nerve in the pig It leaves the 
cranial cavity through the foramen orbito- 
rotundum and courses along the pterygo- 
palatine fossa tp enter the infraorbital canal 
At the pterygopalatine fossa it gives off from 
its dorsal aspect the zjgomaticofacial branch 
and the accessory zygomaticofacial branch, 
which are closely associated (Fig 46-9) 
They perforate the penorbit and course on the 
external surface of the rectus lateralis muscle 
along the lateral wall of the orbit Near the 
orbital ligament the zygomaticofacial branch 
divides into three to four twigs which reach 
the skin of the lower lid The accessory zygo- 
maticofacial branch diverges rostrally from 


the zygomaticofacial branch and terminates 
in the skin adjacent to the media! angle of the 
eye Although variable in the specimens, the 
maxillary nerve contributes with some fibers 
to the formation of the zygomaticotemporal 
branch described under the ophthalmic nerve 
Close and medial to the origin of the last two 
branches, the maxillary gives ofT the strong 
d>communicating branch with the oculomotor 
nerve (Figs 46-9 and 10) This branch, 
coursing dorsad reaches the ventral branch 
of the oculomotor nerve at the dorsolateral 
border of the rectus vcntralis muscle Some of 
its fibers do not course along the ventral 
branch of the oculomotor nerve, but, crossing 
it, they reach the ciliary ganglion From its 
lateral aspect the maxillary nerve gives off 
the caudal maxillary alveolar branches (Fig 
46-8) They number two or three and, after 
passing over the maxillary artery, penetrate 
the maxillary tuber and innervate the molar 
teeth 

The maxillary nerve furnishes, from its 
ventral border, the pterygopalatine nerve. 
This nerve runs ventrorostrad and in young 
animals is covered by the well developed 
maxillary tuber The nerve receives several 
fibers from the pterygopalatine ganglia and 
plexus and gives ofT the lesser palatine nerve 
to the soft palate The pterygopalatine nerve 
then penetrates the corresponding foramen 
and divides into caudal nasal and greater 
palatine nerves The caudal nasal nerve 
reaches the nasal cavity and divides into 
medial and lateral branches The medial 
branch runs rostrad, at first on the lateral 
side of the nasal cavity and later on the floor 
under the mucosa It sends fine twigs to the 
ventral nasal concha and the septum nasi and 
terminates in the mucosa of the rostral por 
tion of the floor of the nasal cavity The lateral 
branch curves around on a bony sulcus on the 
rostral portion of the lateral mass of the eth 
mold bone and reaches the mucosa of the 
maxillary sinus The greater palatine nerve is 
constituted by the majority of fibers of the 
pterygopalatine nerve It runs rostrad in the 
palatine canal and distributes chiefly In the 
hard palate and gum It also sends off some 
twigs to the soft palate 
The infraorbital nerve is the continuation 
of the maxillary nerve in the infraorbital 
canal In the canal it gives off the middle 
maxillary alveolar branch Before leaving the 
canal the nerve gives off the rostral alveolar 
branch, which penetrates the alveolar (in 
cisive) canal and innervates the canine and 
incisor teeth as well as the corresponding por 
toons of the gum The maxillary dental plexus 
formed by the alveolar branches gives rise to 
maxillary dental branches to the premolar 
teeth and the maxillary gingival branches to 
the gums 



46— PORCINE NERVOUS SYSTEM 


1375 


As it emerges from the infraorbital foramen 
the infraorbital nerve divides into dorsal, 
middle and ventral groups of branches. The 
dorsal group constitutes the small external 
nasal branches The middle group is usually 
constituted of three very strong internal nasal 
branches which 1 supply the nostrils and snout. 
The ventral group is formed by the maxillary 
labial branches They are four to eight in 
number. 

The pterygopalatine ganglia (Fig. 46-10) 
are located on the wall of the pterygopalatine 
fossa and are covered laterally by the maxil- 
lary and pterygopalatine nerves They are 
four to eight in number, small, grayish gan- 
glia, united by a large number of fibers and 
giving the appearance of a large plexus The 
plexus is connected by several twigs with the 
maxillary and pterygopalatine nerves. A large 
number of fibers originate from the dorsal 
margin of the plexus and course dorsad to 
Teach the penorbit, into which they penetrate 
The nerve of the pter>goid canal, after emerg- 
ing from the pterygoid canal, courses dorsad 


and distributes in the caudal margin of the 
plexus and ganglion 

Mandibular nerve. The mandibular 
nerve (Figs. 46-7 and 1 1) leaves the cranial 
cavity through the lateral portion of the 
foramen lacerum. At its exit the nerve is flat 
and large and covers the rostrolateral portion 
of the tympanic bulla. It runs ventrad, ros- 
trad and a little laterad, at first between the 
tympanic bulla and the pterygoideus lateralis 
muscle and then on the dorsal surface of the 
pterygoideus medialis muscle where it divides 
into two terminal branches— the mandibular 
alveolar and lingual nerves Close to its exit 
from the foramen lacerum, the mandibular 
nerve gives off the buccal, masseteric and 
deep temporal nerves The masseteric and 
deep temporal originate in a common trunk 
(masticator nerve) They innervate the mas- 
seter and temporalis 

The masseteric nerve (Fig. 46-8) runs la- 
terad, crosses over the mandibular notch and 
reaches the deep surface of the masseter 
muscle m which it ramifies The deep lem- 



FIGUKK 16-11. Intimation of the larjnx and pharynx of the pig, lateral view (scmlsehematie). 


A.eterphaffur cut, B. trachea, cut. C. cricothyroldeu*. D. xternothymidrux E.cricopharynzcux, F, ttmopharmccu* C 
».•« cmohyotdeu, J. omohyoideux, K. .tylohyoldrux, U M? 

0 r r s< ’, ldcu ' , p - common carotid a . Q lingual a , It. occipital a . S.ascendlng p!iaryngeala.,T 

*•. "*“* **■« * car0lid *j nu * 3. pharyngeal branch of j. 4, branch to xtylo 

r in i 'n lingual branch of I. 6. xagux n . 7. pharyngeal branch of C. 8. rtophagea} Irraneh, 9 dtxtal gan 
*li<m of 6 10, cranial laryngeal n. II. external branch of 10 , 12. Internal branch of 10. 13. atx exxorv u. 14 externa] 

«c trurx 20, nand talar n, 21. lingual a, 22 mandibular alveolar n, (From Codin ho. 10C0.) 



1376 PORCINE 


poral nerve to the temporalis muscle frequent 
ly arises from the masseteric nerve 
The buccal nerve (Figs 46-8 and 12) tra 
verses the structure of the pterygoideus later 
nb s muscle to run between the latter and the 
ventral portion of the temporalis muscle Here 
it sends off a small twig to the temporalis mus 
cle Then the nerve curves m a twisted manner 
around the maxillary tuber where it is joined 
by the buccal artery and vein The nerve splits 
into several branches which piercing the 
buccinator muscle ramify in the mucosa of 
the cheek It also sends off branches which 
connect with those of the dorsal and ventral 


branches of the facial nerve The lateral 
pterygoid nerve is a small twig which de 
taches from the initial portion of the buccal 
nerve and penetrates the caudal border of the 
pterygoideus lateralis 

The medial pterygoid nerve arises from the 
rostral border of the mandibular nerve It fol 
lows the course of the parent trunk caudal to 
and parallel with the pterygoid crest, to reach 
the pterygoideus medialis muscle In the ma 
jonty of cases the medial pterygoid nerve gives 
nse to the nerve to the levator and tensor veil 
palatini It is a small twig which traverses the 
otic ganglion and terminates in the lateral sur 



FIGURE 46-12 Nerves of the face and ear of the pig (semisehemalie) 

A auricular cartilage B anular cartilage C zygomatic proee*, of temporal tone D lacrimal foramina E Infraorbital 
foramen 1 internal auricular a. 2, auriculopalpebra] n. 3 caudal auricular n 4 parotid branches 5 transverse facial 
® Mylohyoid branch 7 cervical branch 8 dornl buccal branch 9 ventral buccal branch 10 communicating 
branch of 11 to 2 1 1 auriculotemporal n. 12 caudal auricular n tmuxuUr branch) 13 rostral auricular branch** of 
aunculopaipeorai n. 14 frontal n IS zygomatic branch of auriculopalpebra] n 16 muscular branch of 8 17 bucealn. 
(From Godinho and Cetty 1968b ) 



46— PORCINE NERVOUS SYSTEM 


1377 



FIGURE 46-13. Nerve* of the superficial lateral surface of the head of the pis (aemischematic). 

A, parotid gland; B, helicis retroauricularis (Nikolai. 1954); C, scutuloauricularis superficial^; D. tragohelicine m.; E. 
styloauricularis; F, parotidoauricularls (cut); G, Interscutularis; H, frontoscutularis; I. levator anguli ocull medialis; J, or- 
bicularis oculi; K. malaxis (cut); L. levator labli maxillaris; M, depressor labil maxillaris; N, canlnus; O. levator nasola- 
blalia (cut); P. masseter; Q, parotid duct; R, facial v.; S. zygomaticus (cut); T, eutaneus faciei (cut); U. orbicularis oris; V, 
depressor labii mandibularis; W, mentalis; X. trapezius; Y. brachiocephalicus; Z, omotransversarius; 1, cervical branch of 
facial n.; 2, caudal auricular n.; 3, zygomatic branch of auriculopalpebral n.; 4, rostral auricular branches; 5, com- 
municating branch of 6 to 3; 6, branches of transverse facial branch; 7, frontal n.; 8. muscular branch of 9; 9, dorsal buc- 
cal branch; 10, buccal n.; 1 1 , connecting branch of 12 to 9; 12, ventral buccal branch; 13, external nasal branch; 14, men- 
tal nn.; 15, lateral branch of mylohyoid n. (From Godmho, 1966.) 


faces of the latter muscles. Another slender 
branch penetrates the auditory tube to supply 
the tensor tympani muscle. 

The auriculotemporal nerve (Figs. 46-8 
and 12) detaches from the caudal border of 
the mandibular nerve. It courses caudad 
and then laterad around the caudal border 
of the ramus of the mandible. On the deep 
surface of the parotid gland it splits into the 
following branches; (1) the transverse facial 
branch, which has a variable arrangement (in 
the majority of cases it divides into two 
groups of twigs: the dorsal one ramifies in the 
skin of the cheek, the ventral group ramifies 
in the skin of the masseteric region); (2) a 
strong connecting branch, which is often 
seen joining the dorsal buccal branch of the 
facial nerve; (3) parotid branches to the 
parotid gland; and (4) rostral auricular nerves 
which, coursing dorsad, join the branches of 
the auriculopalpebral nerves. The nerve to 
the external acoustic meatus and filaments to 
the tympanic membrane arise from the 


auriculotemporal nerve in man (Goss, 1966) 
and are also listed in the N.A.V. (1968). 

The mandibular alveolar nerve (Figs. 46-8 
and 11) is the lateral branch resulting from 
the bipartition of the mandibular nerve. After 
a short course it releases the mylohyoid nerve 
(Fig. 46-8) and penetrates the mandibular 
foramen. The dental and gingival branches 
of the mandibular nerve are arranged like 
those of the maxillary nerve. Inside the man- 
dibular canal it also gives off the mental 
nerves (Figs. 46-8 and 13). These are usually 
two in number and, after a short course in- 
side the canal, they traverse the mental 
foramina They distribute in the skin of the 
rostral portion of the lower jaw. The mylohyoid 
nerve passes along a slight groove in the 
medial surface of the ramus of the mandible 
and then on the dorsal face of the pterygoid eus 
medialis muscle close to its mandibular 
insertion. At the rostral margin of the muscle 
the mylohyoid divides into the lateral and 
medial branches. The former curves sharply 


1378 


PORCINE 



FIGURE 46-11 Lateral view of mandibular ganglion and related structures of the pig (semischematic) 

A Styloglossus B pferygoideus lateralis C pterygo deus medialls D hyoglossus E mandibular duct F geniohyoi 
deus G mylohymdeus H buccal gland I longue J sublingual gland 1 lingual n. 2 sublingual n 3 communicating 
branches with lingual n 4 mandibular ganglion 5 branches to mandibular and sublingual glands 6 hypoglossal n 7 
muscular branches of hypoglossal n (From Godinho and Getty 1970 ) 


ventrad and caudad to course parallel with the 
facial artery where penartenal sympathetic 
fibers are incorporated in the nerve It then 
crosses laterally the belly of the digastncus 
muscle here several parotid branches are re 
leased to the deep surface of the ventral por 
tion of the parotid gland At this point it crosses 
the ventral buccal branch of the facial nerve, 
with which some fibers are exchanged The 
branch finally passes through the ventral por 
tion of the cutaneus faciei and distributes to 
the skin of this region The medial branch 
represents the direct continuation of the mylo 
hyoid nerve It courses rostrad on the lateral 
surface of the mylohyoideus muscle and me 
dial to the digastncus muscle Both muscles 
receive innervation from this branch At the 
rostral border of the mylohyoideus muscle, it 
pierces the superficial fascia of the rostral 
portion of the intermandibular space and dis 
tributes in the skin 

The lingual nerve (Figs 46-8 11 and 14) 
after separating from the mandibular alveolar 
nerve passes over the pterygoideus medialis 
muscle where it is joined by the chorda tym 
pam Here it furnishes a branch to the isthmus 
faucium At the rostral border of the ptery 
goideus medialis muscle or a little rostrad it 
sends off the slender sublingual nerv e The lat 
ter courses onward between th e dorsal and ven 
trai portions of the sublingual gland to which 
it gives some twigs Then it follows the course 
of the mandibular duct and finally innervates 
the mucosa of the rostral floor of the mouth 
The Ungual nerve after giving off the sub 
lingual nerve describes a medial curvature 
around the rostral border of the pterygoideus 
medialis muscle where it emits a senes of 
fibers to the mandibular ganglion Connec 
tions between the Ungual and hypoglossal 
nerve are frequent 


The otic ganglion is inconstantly found on 
the rostromedial side of the mandibular nerve 
It has an irregular semilunar shape and is 
closely adhered to the mandibular nerve by 
means of several twigs 
The mandibular ganglion (Fig 46-14) is a 
single, small round node 2 to 3 mm in 
diameter, located on the dorsal aspect of the 
mandibular duct where the latter crosses the 
lateral surface of the caudal end of the sub- 
lingual gland It is connected with the lingual 
nerve by five to ten fine communicating 
branches with the Ungual nerve The ganglion 
gives off several glandular branches to the 
mandibular gland which travel caudally along 
the mandibular duct and penetrate the hilus 
of the gland It also furnishes branches to the 
sublingual gland 


Abducent Nerve (VI) 

The abducent nerve (Figs 46-7 and 10) 
arises from the medulla oblongata just lateral 
to the pyramid and caudal to the pons It courses 
rostrad on the floor of the cranial cavity, 
pierces the dura mater and traverses the 
rostral epidural rete mirabile where it re 
ceives fibers from the internal carotid nerve 
The abducent nerve courses medial to the tn 
gemmal nerve, in company of which it leaves 
the cranial cavity passing through the fora 
men orbitorotundum In the orbit it passes 
over the maxillary nerve and rostral to the 
ophthalmic It then gives off branches to the 
dorsal and ventral portions of the retractor 
bulbi muscle Near the orbital insertion of the 
rectus lateralis muscle, the nerve divides into 
two mam branches and reaches the medial 
face of that muscle In 5 per cent of the cases 



46 —PORCINE NERVOUS SYSTEM 1379 


the abducent nerve furnishes fibers to the 
rectus ventralis 

Facial Nerve (Vil) 

The facial ncne anses from the brain im- 
mediately caudal to the pons at the lateral part 
of the trapezoid body It reaches the internal 
acoustic meatus together with the eighth 
nerve Here the facial nerve diverges rostrally 
and enters the facial canal In the facial canal 
it presents the geniculate ganglion and gives 
off the following branches (1) The greater 
petrosal nerve leaves the geniculate ganglion 
and courses ventrad and a little rostrad, 
passing underneath the trigeminal ganglion 
It traverses the internal carotid plexus where 
it receives a small branch, the deep petrosal 
nerve, from the internal carotid nerve The 
greater and deep petrosal nerves unite and 
then penetrate the pterygoid canal as the 
nerve of the pterygoid canal, and, by way of 
this passage, reach the pterygopalatine fossa 
to terminate in the pterygopalatine plexus, 
(2) Branches to the stapedius muscle, which 
is situated close to the facial nerve and (3) the 
chorda tympani, which anses from the facial 
nerve at the dorsal portion of the facial canal, 
the chorda tympani then pursues a recurrent 
course to reach the tympanic cavity It tra 
verses the tympanic cavity from the caudal to 
the rostral wall, coursing between the handle 
of the malleus and the long branch of the incus 
It re enters the bone through the petrotym 
panic fissure and, after leaving the latter, 
courses ventrad and rostrad to join the lingual 
nerve 

In the stylomastoid foramen the facial 
nerve is joined by the auricular branch of the 
vagus At its, exit from the stylomastoid fora 
men the nerve gives off a senes of branches 
The caudal auricular nerve (Fig 46-22) 
anses close to the stylomastoid foramen, runs 
dorsad and divides into caudal and rostral 
branches Both run in company with the 
caudal auncular artery and internal auncular 
branch The caudal branch is the smaller and 
innervates the cervicoaunculans profundus 
muscle Some of its twigs may reach the trans 
verse and oblique auncular muscles as well as 
the parotidoaunculans muscle The rostral 
branch continues dorsad and passes between 
the retroauricular fat pad and the ventral sur 
face of the cervicoaunculans profundus mus 
cles At a vanable level between the temporo 
mandibular articulation and the ventral 
surface of the cervicoaunculans medius mus 
cle, the rostral branch gives off a fine branch 
to the styloaunculans muscle This branch 
passes, depending upon the site of ongin, 
under the cervicoaunculares profundus and 


medius muscles and around the auricular 
cartilage At the rostral surface of the latter, it 
courses under the scutuloaunculans superfi- 
ciahs muscle and the dorsal portions of the 
scutuloauncularis profundus muscle Then it 
penetrates the hclicme fissure of the auncular 
cartilage where it releases fibers to thehelicine 
muscle and terminates in the styloaunculans 
muscle (Fig 46-13) 

The internal auricular brahch (Fig 46-12) 
ramifies in the skin of the inner surface of the 
auncular cartilage This nerve, after ong- 
mating from the dorsal edge of the facial 
nerve, divides into two to three branches be- 
fore perforating the auncular cartilage 

The auriculopalpebral nerve (Fig 46-12) 
courses dorsad, exchanges twigs with the 
auriculotemporal nerve and divides into ros 
tral auncular branches which innervate the 
aunculares rostrales muscles and a zygomatic 
branch to the frontoscutulans, levator anguli 
oculi medialis, and orblculans ocuh muscles 

The dorsal buccal branch (Figs 46-8, 12 
and 13) anses from the facial nerve in a com- 
mon trunk with the aunculopalpebral nerve 
It emerges between the parotid gland and the 
masseter muscle and courses in the lateral 
surface of the latter along the dorsal margin of 
the cutaneus faciei muscle Here it sends off 
a twig which runs dorsad and supplies the 
orbiculans ocuh and malans muscles Then 
the dorsal buccal branch passes medial to the 
zygomaticus muscie At the rostral border of 
the masseter it forms an extensive plexus with 
branches of the buccal nerve and entrai 
buccal branch From the plexus several twigs 
are given off to the orbiculans ons, depressor 
labn mandibulans, zygomaticus and buc 
cinator muscles Leaving the plexus, the dor- 
sal buccal branch bends dorsad and rostrad 
and, after a short course, divides into caudal 
and rostral groups of branches The caudal 
group runs under the depressor labii maxil 
laris and the caninus muscle and releases 
several fibers to them to finally end in the 
levator labu maxiUans The rostral group con- 
tinues rostrad and medial to the tendon of the 
above muscles to become associated with 
branches of the infraorbital nerve 
The ventral buccal branch (Figs 46-8, 12, 
and 13) passes ventrad and rostrad, covered 
by the parotid gland, and rostral to the man 
dibular gland and lymph node Then it courses 
in company with the parotid duct At the 
ventral border of the masseter muscle it re 
ceives anastomotic twigs from the lateral 
branch of the mylohyoid nerve The nerve 
runs along the ventral border of the masseter 
muscle and, as soon as it courses dorsally, 
gives off the communicating branch with the 
dorsal buccal branch The latter, following the 
course of the facial vein and parotid duct, 



1380 PORCINE 


sends some twigs to the depressor labii man 
dibulans and cutaneus faciei and buccinator 
muscles contnbutes to the formation of the 
plexus at the angle of the mouth and finally 
anastomoses with the dorsal buccal branch 
The ventral buccal branch, which is some 
times double continues to run rostrad along 
the lateral surface of the body of the mandible 
and divides into several twigs to the ventral 
portion of the cutaneus faciei and mentalis 
muscles and the depressor labu mandibulans 
Some of these twigs communicate with 
branches of the mental nerves 
The stylohyoid branch (Figs 46-8 and 12) 
emerges from the ventral edge of the facial 
nerve It courses ventrad on the lateral face 
of the occipitohyoideus muscle and crosses 
the maxillary artery, where sympathetic fibers 
associate with it It then passes over the 
lateral surface of the stylohoideus muscle and 
penetrates its rostral border 
The cervical branch (Figs 46-12 and 13) 
emerges together with the ventral buccal 
branch It pierces the parotid gland and ter 
minates in the cutaneus faciei muscle It 
also supplies the parotidoaunculans muscle 


Vestibulocochlear Nerve (VIII) 

The vestibulocochlear nerve arises from the 
medulla in close association with the facial 
nerve and penetrates the internal acoustic 
meatus where it divides into two parts— 
vestibular and cochlear The vestibular part 
distributes to the utricle, saccule and ampullae 
of the semicircular canals The cochlear part 
ends at the base of the cochlea where its 
fibers penetrate to end in the spiral ganglion 


Glossopharyngeal Nerve (IX) 

The glossopharyngeal nerve (Figs 46-11 
and 15) is connected with the medulla by a 
linear series of roots They perforate the dura 
mater and leave the cranial cavity through the 
jugular foramen in company with the vagus 
and accessory nerves It exhibits, according 
to Frewein (1965) a spindle shaped proximal 
ganglion which relates closely to the proximal 
ganglion of the vagus nerve 

Just outside the cranium it bears the small 
distal (petrosal) ganglion, an ovoid gray mass 
situated close to the proximal ganglion of the 
vagus The slender tympanic nerve emerges 
from the ganglion and, after a short course, 
penetrates the small tympanic canaliculus in 
the petrous portion of the temporal bone to 
innervate the tympanic membrane The 
glossopharyngeal nerve then runs ventrad 
and rostrad caudal to the tympanic bulla and 
crosses laterally the ascending pharyngeal 


artery where it sends off the branch to the 
carotid sinus (Figs 46-11 and 15) Then the 
nerve emits the pharyngeal branch (Figs 
46-11 and 15), which soon unites with the 
pharyngeal branch of the vagus and sympa 
thetic fibers from the cranial cervical gan- 
glion to constitute the pharyngeal plexus. The 
plexus sends branches to the muscles of the 
pharynx and soft palate, with the exception 
of the tensor and levator veil palatini The 
glossopharyngeal nerve passes caudal to the 
stylopharyngeus caudalis muscle and releases 
a short branch to it The nerve then reaches 
the lateral surface of the pharynx and, after 
piercing the hypopharyngeus muscle as the 
lingual branch, penetrates the tongue caudal 
to the insertion of the hyoglossus muscle Here 
it sends off a branch to the mucosa of the 
pharynx. 


Vagus Nerve (X) 

The vagus nerve (Figs 46-11 and 15) ong 
mates at the lateral surface of the medulla 
oblongata in close association with theacces 
sory nerve and leaves the cranial cavity 
through the jugular foramen together with 
the latter and the glossopharyngeal The flat 
and small proximal (jugular) ganglion hes at 
the entrance of the jugular foramen The 
auricular branch arises from the ganglion and 
runs laterad and ventrad to jom the facidl 
nerve in the facial canal near the stylomastoid 
foramen The vagus runs caudad and ven 
trad forming with the accessory nerve 
a fold in which the hypoglossal nerve courses 
The nene crosses laterally the ascending 
pharyngeal artery and furnishes the pharyn 
geal branch (Fig 46-11) The latter takes part 
m the formation of the pharyngeal plexus 
It gives off the esophageal branch (pharyngo- 
esophageal nerve), which travels caudally on 
the lateral face of the larynx, sends off 
branches to the thyropharyngeus muscle and 
continues caudally tp supply the proximal 
portion of the esophagus, into whose mus 
culature it penetrates The vagus bears a 
well developed distal (nodose) ganglion (Figs 
46-11 and 15) located dorsal to the common 
carotid artery The cranial laryngeal nerve 
leaves the vagus at the distal ganglion At the 
lateral side of the larynx it divides into two 
branches- external and internal The external 
branch is the smaller, it runs parallel to the 
esophageal branch and terminates in the 
cricothyroideus muscle The internal branch 
is the actual continuation of the cranial laryn 
geal nerve It penetrates the lateral wall of 
the larynx and innervates the laryngeal 
mucosa. 

At a variable distance from the distal gan 
gUon the vagus joms the sympathetic trunk. 



46— PORCINE NERVOUS SYSTEM 


1381 



FIGURE 16-15 Innervation of larynx and phar) nx or the pnr medial me* (semnehe 

. . ■ roftiHni G Pf 


riuuut innervauon oi „ , 

t? ji «r nhirvneeal a. F levator veil palatini G esophagus 

A atlas B axis C common carotid a. D occipital a. E ascencung pnanr s ^ 8terno hyoideus 1 glossopharyngeal 
H epiglottis 1 cricoid cartilage J lateral laryngea 1 _ J^nch of 1 6 vagus n 7 pharyngeal branch of 6 8 

n 2, carotid sinus branch 3 4 pharyngeal branches of 1 5 lingual o DharYn geal branch of 8 12 external carotid n 
cranial cervical ganglion 9 sympathetic trunk 10 internal c vagus n. 16 distal ganglion of 15 17 cranial 

13 communicating branch with first cervical n 14 first cervical n 
“cyngeal n 18 hypoglossal n (From Godlnho 1966) 


and they are held in a close association by a 
common connective tissue sheath down to 
the seventh cervical vertebra- In the caudal 
third of the cervical course, the left vagus 
Rhes off one or two branches which ac 
^° m pny the vagosympathetic trunk toward 
the heart The nght vagus enters the thorax 
^Jia passes ventral to the subclavian artery 
Here it furnishes the nght recurrent laryngeal 
nerve, which turns around the subclavian 
nrtery and ascends in the neck on the ventro- 
literd side of the trachea. The recurrent 
nryngcal nerve terminates as the caudal 
laryngeal It is the motor nerve to all the in 
tnnslc muscles of the larynx with the ex 
ceptionof the cricothyroid e us After giving off 
me recurrent laryngeal nerv c the right vagus 
Passes caudad crosses the medial surface 
^^^stoccrvicovertebral venous trunk and 
i ™ lateral surface of the trachea and 
iviiies into dorsal and ventral branches The 


left vagus enters the thorax, courses caudad 
along the lateral surface of the aortic arch and 
gives off the left recurrent laryngeal nerve, 
which courses around the aorta and runs ros 
trad on the left lateral face of the esophagus 
and then of the trachea and, in the neck, has a 
similar course to the nght nerve The left 
vagus continues caudad passes over the left 
pnncipal bronchus and divides into dorsal and 
ventral branches . . 

The dorsal and ventral branches unite with 
the corresponding branches of the opposite 
side, forming the dorsal and ventral vagal 
trunks. The dorsal vagal trunk is larger and 
formed mainly by nght vagal nerve fibers 
The ventral vagal trunk Is constituted mainly 
of left vagal nerve fibers The trunks course 
on the dorsal and ventral surfaces of the 
esophagus, respectively, and furnish fibers 
to the latter and to one another In the ab- 
dominal cavity the vagal trunks supply the 



PORCINE 


1382 

parietal and visceral gastnc branches, hepatic 
branches duodenal, pancreatic and intestinal 
branches and terminate in a number of 
plexuses which are descnbed in detail m the 
general autonomic section. Chapter 13 

Accessory Nerve (XI) 

The accessory nerve (Fig 46-8) is formed 
by cranial and spinal roots The latter arises 
from the lateral aspect of the cervical por 
tion of the spinal cord, the former from the 
medulla oblongata in senes with the rootlets 
of the vagus The accessory leaves the cranial 
cavity through the jugular foramen in com 
pany with the vagus and glossopharyngeal 
nerves It runs in association with the vagus, 
crosses laterally to the ascending pharyngeal 
artery and divides into internal and external 
branches The internal branch is relatively 
long and joins the vagus at the distal gan 
glion The external branch courses laterally 
between the brachiocephahcus and stern o- 
cephalicus muscles, where it divides into ven 
trai and dorsal branches The ventral branch 
immediately penetrates the stemocephalicus 
muscle, and the latter courses along the lateral 
aspect of the neck to innervate the trapezius 
muscle The dorsal branch establishes con 
nections with cervical nerves II, III and IV 

Hypoglossal Nerve (XII) 

The fibers of the hjpoglossal nene (Figs 
46-8, 11 and 14) arise from the ventrolateral 
surface of the medulla The nerve leaves the 
cranium through the hypoglossal canal. It 
relates caudally with the vagus and accessory 
nerves Then it passes between the internal 
and external branches of the accessory nerv e 
The nerve then courses ventrad and rostrad 
and releases a branch to the first cervical nerve 
forming the ansa eerviealis It passes medial 
to the stylohyoideus and digastncus muscles 
then lateral to the hyopharyngeus and hyoglos 
sus muscles After sending branches to the 
hyoglossus and geniohyoideus muscles it 
turns medially around the rostral border of 
the latter muscle to ascend in the tongue be 


tween them Connections with the lingual 
nerve are frequently seen 

BIBLIOGRAPHY 


Athlon. E. R. and C E Oxnard. 1958 Variation in the maxillary 
nn\e of certain mammal* ZooJ. Soc. London Proc 138 607- 
€24 

Baptlsta. B V 1944 lnve*tlgac6e* ana ti mica* sabre o* nervo* 
crania no* ventral* cm "vertebra la." Anal* da Academia BraiQ- 
etra de Ctfnria* 16 79-110 

Catania V 1924 II ple**o del tan i) to *otcotrta*ce!lare ed II mo ranto 
farinteo nell uomo ed alciml mammifett Arch. Italia no Anat. 
EmbrioL 2M87 532. 

Fieandl. E. 1914 Ober da* Wurzelgebtet de* Nervu* bypoglassu* 
und den Plexus bypoylorvo cervical bel den Saugetierrn. 
Cegenbaur Morph. Jahrb 48 513-1142 
Fitzgerald. M J T„ and M. E. Law 1958 The peripheral connection* 
between the Ungual and hypoglossal nerv e* J Anat92 178-188. 
Freweln J 1965 Eln Beltrag xur Kenntnls der tentiblen Wtrtel 
fcanglien de* N glotsopharyngeus Zbl Vet. Med.. Reihe A 12 
SJ1 SIS 

Cod mho 1L P 1966 Course and dlitnburion of thenertd craxtaltt 
In the Sut *cr o/u domeittcni A grots anatomical study M.S- 
Thetls Ames. Iowa State University 
Codtnho^JI P, and P_ Getty 1968a. Cro»* anatomy of the nerve* In 
the orbit of the pig. Arqulvo* de EscoLt de Veterinaria (Belo 
Horizonte Brazil) 20 21 31 

Cod to ho 11 P, and R. Cetty 1968b innervation of the ear muscle* 
and associated » tincture* in the pig Arqulvo* de Etcela de 
Vetertnarta (Belo Horizonte Brazil) 20 15-19 
Cod In bo t| P and R. Cetty 1970 Cm* anatomy of the paraiympa- 
thetlc ganglia of the bead In domestic arttodactyla. Arqulvo* de 
E*cola At Veterinaria (Beta Horizonte Brazil) 22 129-139. 
Co**. C M. I960 Gray 1 * Anatomy of the Human Body 28th ed. 
Philadelphia. Lea 5 Eeblgrr 

Crau H. 1941 Da* Cangllon nodosum u merer flauitier *. Deutsche 
tier in tl Wnsch. 51 281 283 

lloltinger A. 1955 Contribution 4 Ktudede la constitution de Tan** 
du nerf hypogloste Arch Anat Ifislcl EmbryoL 38 3-46, 
Johnston, J B 1913 Nervy* terminal;* In reptile* and mammals. 
J Comp Neur 23 97 120 

John* ton. J B 1914 The nervu* terminal 1* in man and mammal*. 
Amt. Pec 8 185-198. 

Law M E 1956 Sensory fiber* In the superior oblique and IV 
cranial nerve In the pig lri*h J Med. Set 6 1*8-77 
Law M. E. and M J T Fitzgerald. 1956 The lateral re«u* muscle 
and lixlh cranial nerve In the pig Nature (London) 178 798-799 
Leibre F X. and P Malgnon. 1907 Sur la part qul rerient 4 la 
brant he anattomotlque du spinal dans le prupnFles physio, 
loglque* du pnnmogaurique ou pneumo-tpioaL J Med. Vet 
Zootech. 2 212-227 

Moustu M 1889 Let nerf* excito-s^cretolre* de la pajodde cliez le 
cheval le mouton el le port CotnpL Bend. Soc. BloL 41 343-345 
Nikolai. N 1954 Uber d e oberflichltchr Eacialsmuskulatur des 
Schwelne* (Sus scrofa) Cegenbaur Morph Jahrb 93 321 363 
Nitschke Th. 1972 Zur makrovtopiKben Anatomic der Gebiraner 
ven de* llaustchweinr*. 1 Tetl Die nn. encephah I IV AM. Vet 
med 1 212 236 1973 2. Teil Die Nn encephah V VI Ibid. 2 
78-103. 1973 3 Teil Die Nn encephall Vll VIII find 2 187 
208 1973 4 TrU Nn. encephah IX XI ibid. 2 354-383 1974 5 
Tetl Der N encephaltcu* XII hypoglottu* ibid. 3 142-181 
Wedgewood. M 1962. Caine of the Inctitve nerve In the pig. (Ab- 
stract) J Dent- Re*. 41 1263 

timelier C 1936. La double Innervation de* muscle* extrinsFque* 
de Joed cher Sut scrota domrittcus et Sut scrofa. Ann. d Oculist 
(Paris) 173 453-466 

W lu ckie r C 1937 LlnneTvatJon sensitive* et morrice de* muicle* 
extnntequet de I'oeO chez quejque onzufds. Arch Arab HtstoL 
Embryo) 23 219-234 



46— PORCINE NERVOUS SI STEM 


1383 


SPINAL NERVES 


by N G Ghoshal 


The spinal nerves of the domestic pig 
resemble those of the horse in origin, branch 
ing and general disposition There are usually 
39 pairs cervical (8), thoracic (usually 15) 
lumbar (usually 6) sacral (4) and caudal or 
coccygeal (usually 6) However, the number 
vanes widely, depending on the thoracic 
(14 to 16) and lumbar (5 to 7) vertebrae pres 
ent in different breeds (Fig 46-16) 


Cervical Nerves 


The cervical nerves number eight pairs 
eacb exhibiting the characteristics ofh typical 
spinal nerve The dorsal branches emerge 
irough the lateral vertebral foramina of the 
corresponding vertebrae whereas the ventral 
nches emerge through the intervertebral 
foramina (Gandhi and Getty 1969a) There 
re me former he along with the correspon 
orng cervical vertebra and the latter caudal to 
SSiiS”® vertebra (Fig 46-17) The dorsal 
diviri heS exce P f tbe first cervical nerve, sub 
thn ,1 l °, mecbj d and lateral branches All 

eighth* 131 branclles except the first and 
thf » minate as cutaneous nerves along 
rsal aspect of the cervical region (Fig 


46-1 8) The ventral branch of the first cervical 
nerve communicates with the hypoglossal 
nerve constituting the ansa cervwahs The 
lateral components of the ventral branches of 
the second third, fourth and fifth cervical 
nerves furnish the cutaneous innervations of 
the \ entrolateral and ventral aspects of the 
cervical region The great auricular nerve and 
the transverse cervical nerve arise together 
from the combined trunk of the second and 
third cervical nerves The dorsal branches of 
the fourth fifth and sixth cervical nerves 
usually communicate with each other, form 
ing the dorsal cen ical plexus (Fig 46-19) 
similar to that of the horse A similar ventral 
cervical plexus is frequently formed by the 
ventral branches between the second to 
eighth cervical nerves (Fig 46-16) as in the 
horse and ox 


Phrenic Nerve 

The phrenic nerve is formed by the union of 
the ventral branches of the fifth sixth and 
seventh cervical nerves The roots from the 
fifth and seventh cervical nerves are usually 
slender They converge to a single trunk at 
the level of the seventh cervical vertebra 



^ 46-16 Cutaneous branches of cervical thoracic lumbar and sacral nerves right lateral view 

«f ® caudal cutaneous femora! n F lateral cutaneous femora! n a cervical and a , thoracic parts 

1 m u«dor*| ( . . ^'^cphallcua d stemoccphalicus c omotransversarius f omohyoideus g stemothyroideus h latls 
® ® lJmeobi Ce _ g lt,Uu * ex,cmu * abdominis j serratus dorsalis caudalis m pectornlis asccndcns n tensor fasciae laute 
.P* P *emltcndinosu* q semimembranosus r longissimus u gluteus medius C,a C,a media! branches 
I V* 1,4 me*ii t l*’5 tv * ca * nerves J1 to VI! C, ,b C, ,b lateral branches of Ventral branches of cen leal nerves II to 
umbaj nerves li of dorsal brand es of lumbar nn 1 to VI L-,a L»a lateral branches of dorsal branches of 

“5? n cbei <,r '-»■ cranial clunlal nn ) L,b lateral branch of il ohypogastric n S a S,a lateral branches of dor 

*»• T (> * fi t . . r T , l ’ m * *° *•! (middle clunlal nn > Ta T a medial branches of dorsal branches of thoracic nn I to 
EftMtaj t>ranc ‘ cs or dorsal branches of thoracic nn. II to XV Tb \entral euUneous branch of Intercostal n. 

>rtmary branch) Tb T V lateral cutaneous branches of Intercostal nn. V to XIV Tb“ lateral twigs 
oranch T,b** T ,b~ lateral mammary branches (From Gandhi and Getty 19G9* and c ) 




FIGURE 46-17. Dorsal and ventral branches of cervical, thoracic, lumbar and sacral nerves; right lateral 
view, schematic. 

II, Lateral thoracic n., A, great auricular n., F, lateral ctitaneou* femoral n., G, II, lateral vertebral foramina, C,a'-C,a', 
medial branches of dorsal branches of cervical nn I to VII, C,b-C,b, ventral branches of cervical an. I to VIII, C,b'. medial 
branch of ventral branch of cervical n. IV, C,tr C.b'. lateral branches of ventral branches of cervical nn. Ill to V, L,a' I*a\ 
medial branches of dorsal branches of lumbar an. I to VI, L .a'-Ua", lateral branches of dorsal branches of lumbar nn. I to 
VI, L,b, ventral branch of lumbar n. IV, L,b'-L,b‘, lateral branches of ventral branches of lumbar nn I and II, L,b'-L,b', 
medial branches of ventral branches of lumbar nn- 1 and II, S,a Sa dorsal branches of sacral nn. I to IV, £,b-S]b, ventral 
branches of sacral nn. I to III, T,a‘-T„a’, medial branches of dorsal branches of thoracic nn. I to XV, T,a'-T„a'\ lateral 
branches of dorsal branches of thoracic nn. I! to XIV. T,b-T u b, ventral branches of thoracic nn II to XI!I;T,b'-T u b', ven- 
tral cutaneous branches of Intercostal nn (including medial mammary branches), T,»b\ ventral cutaneous branch of co*- 
toabdomlnal n. . Td)'-T„b", lateral cutaneous branches of intercostal nn. (From Gandhi and Getty, 1969a. b, and c ) 




FIGURE 46-18. Dorsal and ventral cervieal pi erases and cutaneous branches of thoracic and lumbar 
nerves, deep dissection right lateral view. 


9, Long thoracic n.. 11, lateral thoracic n. A. great auricular n.. F lateral cutaneous femoral n ; V. wimiiI jugular v , b 
brachiocephalicus (cut). <S, stemocephalicus i obbquus externus abdominis j*. retractor costae, t, obbquus intemus ab- 
dominis, 1. transversus abdominis, m, pectoralis ascendeas, r, r .longissimus *, in teicos tales extern! s’ intercostales in- 
temi, t, iliocos tails. W, scalenl, x', intertranssersani ventrales cervids, C,a'-C.a', medial branches of dorsal branches of 
cervical nn. II to VIII, C.b^l.b ' entrai branches of cervical nn. f to VIII C.b , medial branch of ventral branch of cervical 
n. IV, C, . »b\ C«b", C, . »b% lateral branches of ventral branches II and HI. IV, and IV and V. L^a" L^»'. medial branches of 
dorsal branches of lumbar nn. U to V l-a'-L»a' lateral branches of dorsal branches of lumbar nn. I! to VI, L,b\ lateral 
branch of ventral branch of lumbar n. II, T,a‘ TuA'. medial branches of dorsal branches of thoracic nn. I to XV. T,a' T^A~. 
lateral branches of dorsal branches of thoracic nn. I to XV Tb\ ventral cutaneous branches (including medial main mar* 
branches); T,b" T M b*, lateral cutaneous branches of intercostal nn., T a b\ lateral cutaneous branch of costoabdominal B- 
(Ftota Candhi and Cetty, 1969 a and b ) 



46 - PORCINE NERVOUS SYSTEM 


1385 



uidcniocepnaUcus (cut) d stemocephalicus 1 oDuqu«» trtmsversus abdominis m peciorau* 

dor^Us cranlalis j\ retractor costae k obilquus internus a J )d °" lim , talis * serratus ventralis thoracis, w . scaleni 
\f t ' l°ngisslmus, s, intercostales exterru, s . intercostales mterrn cervicis z, semispinalis capitis, C,a C T , 

x . imertransversarh ventrales cemcis, y rhomboideus ca P*| is y . ventra i branch of cervical n I. C.b', medial branch 
medial branches of dorsal branches of cervical nn II to VII branches of cervical nn II and III IV. and 

ventra^ branch of cervical n IV. C ,♦,«*. C.V C, lateral \^^ nches ofdorsa i branches of lumbar no- 

!f' andv . L,a . medial branch of dorsal branch of lumbar n 1 ^3 L * a ranches of dorsal branches of thoracic 

to V|. L,b . lateral branch of ventral branch of lumbar n II. T,a T,, , . xy T b - T,.b' lateral cutaneous branches 
ntL II to XI T.a- T„a’, lateral branches of dorsal branches of thoracic nn I t a cutaneous branch T„b lateral 

o* Intercostal nn T u bMateral branch of costoabdominal n T„b . lateral twi go. 
mammary branch (From Gandhi and Getty. 1969 a and b ) 


Brachial Plexus 

(Fig 46-20) 

. brachial plexus is formed by the ven- 
branches of the fifth, sixth, seventh and 
th ce raical and first thoracic nerves in 
P>B (Table 46-1) 


^ u P«ncopulat Nerve 

.vT* 10 BU Prnseapular nerve is derived from 
branches of the fifth, sixth and 
plcxii 'ru rv * ca * components of the brachial 
* Vhc ner\e enters the interstices bc- 
mu<Jl 11>C su P ra splnatus and subscapularis 
anit.u innervates the former muscle 

the infraspinatus 


Svihuopvdor Nerves 

*rmM*v 1 ^ scapu ^ ar nerres nre usually rep 
Itb'n u, l "° branches They derive ftbf 
%CI ) trn * branches of the sixth a 
T1,c> inner ' a,c ' 


■ctorol Nerves 

The pectoral nerves are usually formed by 
e ventral branches of the sixth sevemh ajd 

BMh derive* fibers es- 

■ntially from the seventhand eighth cerviral, 
herras the caudal pectorals come from the 
i,h and seventh ce'rvical nerves They sup- 

neMnml muscles 


lusculocutaneous Nerve 

IISSS£S|| 

nint bv means of the proximal and dixtal 
1 .XL hranches Tlie medial cutaneous 
nl # S |irLrhlal nerre after emerging between 
he Weeps bmchil and hracl.locephallcu. 
nusclcs innervates the fascia and *Un on 
he cron’iomcdinl aspect of the proxJm.il lliird 



TORCINE 


1388 



HRURF 4B-"22 Nerves of the distal part if the 
right thoracic limb of pig, palmar view schematic 
2 Doiul I ranch of ulnar n 5 cranial twig of caudal cu 
uncous antebrachial n. of ulnir 19 median n. 19 me- 
dial branch 20 palmar branch of ulnar n. 21 deep 
branch 23 palmar common diRltal n U 25 palmar 
(axial) proper dlRltal n III 28 palmar (axial) proper dujl 
Ul n. IV 29 palmar common digital n 111 20 com 
rntmicatlnz branch 31 palmar proper dlcir.il nn (I and 
111 32 palmar common digital n. IV 32 laieral branch 
32* medial branch 33 lateral (abaxlal) palmar digital n. 
\ 3-1 palmar proper digital nn IV and V 35 medial 
(abaxlal) palmar dlgiul n. II (From Chovhal and Cetty 
10G7a.) 


ndtihs and divides in a variable manner Into 
several muscular branches to innervate the 
extensor fcarpi ndialls, extensor digitorum 
communis (Including the extensor digiti HI), 
abductor digiti I longus, extensor digitorum 
lateralis ulnans lateralis and, sometimes the 


brachialis, extensor digiti II and supinator 
(when present) 

Ulnar Nerve 

The ulnar nerve derives its fibers entirely 
from the ventral branches of the eighth 
cervical and first thoracic nerves At the level 
of the lesser tubercle of the humerus it sepa 
rates from the median nerve Within the 
proximal half of the arm it gives off the caudal 
cutaneous antebrachial nerve, which ramifies 
in the fascia and skin approximately halfway 
down on the medial aspect, and the proximal 
third of the caudal aspect of the forearm The 
muscular branches of the ulnar nerve inner 
vate the flexor carpi ulnans, the flexor digi 
torum superficiahs, and the humeral and 
ulnar heads of the flexor digitorum profundus 
and distal to the carpus, the mterossei mus 
cles The ulnar nerve divides usually at a vari 
able level in the distal half of the forearm into 
dorsal and palmar branches Before this 
branching the ulnar nerv e supplies the carpal 
glands 

The dorsal branch after coursing along the 
caudolateral aspect of the forearm furnishes 
twigs to the fascia and skin of the region 
Near the carpus It divides into medial and 
lateral branches (Fig 46-21) The medial 
branch joins the communicating branch of 
the radial nerve (when present) and descends 
as the dorsal common digital nerve IV, which 
finally divides into the dorsal proper digital 
nerves IV and V The lateral branch continues 
distally as the lateral (abaxial) dorsal digital 
nerv e V The palmar branch after having sup 
plied the mterossei muscles by its deepbranch 
divides into a medial and lateral branch (Fig 
46-22) The former descends as the palmar 
common digital nerve IV which receives the 
communicating branch of the median and 
subsequently gives nse to the palmar proper 
digital nerves IV and V The lateral branch 
continues as the lateral (abaxial) palmar digi- 
tal nerve V According to Gottvvald (1969), the 
palmar branch gives nse to the dorsal meta- 
carpal nerves III and IV' which after tra 
versing the corresponding intcrmetacarpal 
spaces join the dorsal common digital nerves 
III and IV of the radial and ulnar respectively 

Median Nerve 

The median nerve demes its fibers entirely 
from the v entral branches of the seventh and 
eighth cervical and first thoracic nerves It 
giv es oft branches to the pronator teres, flexor 
carpi radialis, flexor carpi ulnans and flexor 
digitorum supcrficiafis and profundus mus 
cles A palmar branch or the median arises 
in the distal half of the forearm and joins the 
medial (abaxial) palmar digital nerve II (Gott- 
vvald, 3969) The palmar branch also supplies 



46 — PORCINE NERVOUS SYSTEM 


1389 


the carpal glands. Near the middle of the 
metacarpus the median nerve detaches the 
medial (abaxial) palmar digital nerve 11. The 
place of division of the median nerve is ex- 
tremely variable from the middle of the 
carpus to the distal third of the metacarpus 
(Fig 46-22) At the level of the metacarpo- 
phalangeal (fetlock) joint it divides into 
palmar common digital nerves II and III and 
a communicating branch. The palmar com- 
mon digital nerves II and III finally divide 
into palmar proper digital ner\es II and III, 
and III and IV, respectively Sometimes the 
axial palmar proper digital nerves of the main 
digits communicate with the corresponding 
dorsal nerves through the interdigital space. 
The communicating branch of the median 
nerve joins the palmar common digital nerve 
IV of the ulnar slightly proximal to the meta- 
carpophalangeal joint before it divides into 
palmar proper digital nerves IV and V. 

Long Thoracic Nerve 

The long thoracic nerve derives its fibers 
solely from the ventral branches of the 
seventh and eighth cervical nerves It in- 
nervates the serratus ventralis thoracis mus- 
cle. 


Thoracodorsal Nerve 

The thoracodorsal nerve is formed by the 
ventral branches of the seventh and eighth 
cervical components of the brachial plexus. 
It innervates the latissimus dorsi and some- 
times gives collateral twigs to the teres major 
muscle. 

lateral Thoracic Nerve 

The lateral thoracic nerve receives fibers 
from the ventral branches of the eighth 
cervical and first thoracic nerves. Itinnervates 
the cutaneus trunci and preputialis cranialis 
muscles 


Thoracic Nerves 

(Fig. 46-23) 

There are usually 1 5 pairs of thoracic nerves. 
(They may vary between 14 and 16 pairs 
among the different breeds.) Their pattern of 
origin, branching, distribution, etc., resembles 
that of the horse, except that the dorsal and 
ventral branches leave the vertebral canal 
through the dorsal and ventral lateral verte- 
bral foramina of the corresponding thoracic 




1390 


I'OttCINF 



FIGURE 4fi-2f Dorsal branches of thoracic J JII through lumbar I nrrvea, left lateral no* schematic 


c multlfidut dor»t c levaiore* cosiarum 1 retractor costae k obliquu* tntemus abdominis r lonRltslmu* < inter 
costates extern! s iniercotiaiet inlem) I JJtoeosiali* M mamilljry proc rss L,a L,a medial branches of dorsal 
branches of lumbar nn 1 to V L,a L,a lateral branches of dorsal branches of lumbar nn. I to V T,a T & medial 
branches of dorsal branches of thoracic nn VllltoXV T.a T,a Literal branches of dorsal branches of thoracic nn VIII 
to XV (From Gandhi 19G6> 


vertebrae, respectively (Gandhi and Getty, 
1969b) and do not emerge through the inter 
vertebral foramina (Fig 46-17) The dorsal 
branches further subdivide into medial and 
lateral branches both terminating as 
cutaneous twigs on the dorsal and dorsolateral 
aspects of the thoracic region (Fig 46-24) 
The course of the medial branches of the first 
10 or 11 thoracic nerves is different than that 
of the last fn e or six nerv es depending on the 
degree of development of mamillary proc 
esses The ventral branch or the intercostal 
nerve gives off the lateral cutaneous and the 
ventral twigs of the preceding (lateral mam 
mary), and termination of the ventral branch 
as the ventral cutaneous branches including 
the medial mammary branches (Fig 46-19) 
These are responsible for the innervation of 
the fascia and skin of the lateral v entrolateral 
and ventral aspects of the thoracic region, 
including the thoracic and cranial abdominal 
mammae 

Lumbar Nerves 

The lumbar nerves resemble those of the 
horse in origin and general arrangement 
There are usually six pairs but they may vary 
between five and seven pairs depending on 
the breed As in other regions the dorsal 
branches of the lumbar nerves subdivide into 
a medial and lateral branch both of which 
terminate as cutaneous twigs (Fig 46-16) 
The sensory components of the dorsal 
branches extending over the iliac crest to the 
gluteal region are designated as the cranial 
clumal nerves 

LumbarPJexus 

TV e ventral branches of all lumbar nerves 
are joined to each other by means of com 


mumcating branches (Fig 46-2 7) When 
there are seven lumbar nerves (Reimers 
1913 Ziclzschmann ct a] , 1943), the first 
and second lumbar nerves are called the 
cranial and caudal iliohypogastric nerves, 
respectively as in the dog and cat In that 
case, the ventral branch of the third lumbar 
becomes the ilioinguinal nerve When there 
are five lumbar nerves the Iliohjpogastnc 
nerve is anatomically missmp and its area of 
innervation is functionally taken overby the 
last thoracic nerv e The ventral branches of 
the first to the fourth lumbar nerves innervate 
the paralumbar region of the abdominal wall, 
Including the inguinal caudal preputial, 
mammary and cranial scrotal regions (Fig 
46-25) 

The iliohjpogastnc nerve courses under the 
transverse process of the second lumbar 
vertebra and divides into two branches which 
accompany the caudal phrenic artery It ends 
caudal to the umbilicus innervating the mam 
mary glands of this region The ilioinguinal 
nerve divides In a variable manner to give 
nse to approximately four branches These 
branches innervate the abdominal muscles, 
the fascia of the inguinal region skin of the 
flank mammary glands and prepuce The 
iliohjpogastnc and ilioinguinal nerves are 
the main supply to the abdominal wall, es 
pecially the area caudal to the umbilicus and 
craniomedial to the thigh 
The genitofemoral nerve is formed largely 
by the ventral branch of the third lumbar 
nerve except when it Is formed by the second 
and third lumbar nerves in vvhich case the 
ventral branch of the second lumbar is the 
mam root In the majority of cases it derives 
fibers from the ventral branches of the third 
and fourth lumbar nerves The genitofemoral 
nerve after coursing between the psoas 
major and psoas minor muscles, emerges at 
the level of the fifth lumbar vertebra, being 



46- PORCINE NERVOUS SYSTEM 


1391 





FIGURE 46-25. Innervation of thoracic and abdominal mammary glands; ventrolateral view. 


11, Lateral thoracic n.; F. lateral cutaneous femoral n . a', thoracic part of trapezius; h, latissimus dorsi; i. obliquus ex- 
temus abdominis; j, serratus dorsalis caudalis; m. pectoralis ascendens; r, longissimus; v. senatus ventralis thoracis; L,a"- 
l,a-, lateral branches of dorsal branches of lumbar nn. 1 to IV, L,b\ lateral branch of ventral branch of lumbar n. I; L,b", 
ventral cutaneous branch of lumbar n. II (including medial mammary branches); T»a'-T„a*, lateral cutaneous branches of 
dorsal branches of thoracic nn. V to XV; T,b'-T„b\ ventral cutaneous branches of intercostal nn ; T,»b\ ventral cutaneous 
branch of costoabdominal n; T«b"-T 11 b‘\ lateral twigs of lateral cutaneous branches; T,b“-T, a b'*. lateral mammary 
branches. (From Gandhi, 1966.) 

pect of the tarsus. At the distal third of the 
leg it divides into a medial and lateral branch 
(Fig. 46-27). The lateral branch joins the 
medial branch of the superficial fibular nerve 
to constitute the dorsal common (pedal) digi- 
tal nerve II, whereas its medial branch de- 
scends as the medial (abaxial) dorsal (pedal) 
digital nerve II (Bruni and Zimmerl, 1951; 
Ghoshal and Getty, 1968). According to the 
N.A.V. (1968) and Beer (1968), the latter 
nerve may arise from the superficial fibular 
nerve. In the latter case, the saphenous nerve 
terminates variably either proximal to the 
tarsus or supplies the medial aspect of the 
tarsus or extends up to the middle of the 
medial surface of the second metatarsal. 
The obturator nerve has an origin similar to 
that of the femoral nerve. It innervates the 
intrapelvic part of the obturatorius extemus, 
gracilis, pectineus and adductor muscles. 


Sacra! Plexus 

The large ventral branches of the sacral 
nerves leave the sacral canal and continue 
on the medial wall of the pelvis. The lumbo- 
sacral trunk, makes up a large part of the 
lumbosacral plexus and continues outside 
the pelvic cavity as the ischiatic nerve (Fig. 
phe nous nerve furnishes the fascia and skin, 46-26). 

cranial to the stifle joint, the medial aspect The origin of the cranial gluteal nerve Is 
of the thigh and leg and the dorsomcdlal as- very difficult to ascertain since it is inter- 


cranial to the lateral cutaneous femoral nerve. 
After coursing through the inguinal canal 
it ramifies in the superficial inguinal lymph 
nodes, mammary gland, the preputialis cau- 
dalis muscle (when present) and the prepuce. 
The lateral cutaneous femoral nerve has a 
similar origin to that of the preceding (Bosa 
and Getty, 1969), whereas Montane and Bour- 
delle (1920) describe it as arising from the 
ventral branches of the fourth and fifth lum- 
bar; according to Reimers (1913), it arises 
from the ventral branches of the fifth and 
sixth lumbar nerves. After coursing between 
the psoas muscles it turns sharply Ventral 
and lateral toward the coxal tuber, where it 
pierces the obliquus intemus abdominis 
muscle, or passes between same and the ili- 
acus muscle and descends along the medial 
aspect of the tensor fasciae latae, accompany- 
ing the caudal branch of the deep circumflex 
iliac artery. It is distributed variably to the 
fascia and skin distal to the stifle joint, the 
inguinal region and the flank, including the 
subfliac lymph nodes. 

The femoral nerve has an extremely vari- 
able origin. Frequently the ventral branch of 
the fifth lumbar constitutes the main root, 
hut in exceptional cases the main root may be 
the fourth lumbar. In a variable manner the 
ventral branches of the third to sixth lumbar 
nerves contribute to its formation. The sa- 


1392 


FOIICIM 



twined with the ischiatie and caudal gluteal 
nerve** In the majority of cases it seems to 
dense fibers from the ventral branches of 
the fifth and sixth lumbar and first sacral 
components of the lumbosacral plexus Some 
times the third and fourth lumbar and second 
sacral nerves contnbute variably to its for 
mation It leaves the craniovcntral aspect 
of the plexus and is fairly thick It innervates 
vanably the gluteus medius gluteus pro- 
fundus tensor fasciae latac and piriformis 
muscles The caudal gluteal nerve usually 
denves its fibers from the ventral branches 
of the fifth and sixth lumbar and first and 
second sacral nerves with an inconstant 
contribution from the third and fourth lum 
bar nerves Usually the caudal gluteal nerve 
separates by two strands from the ischiatie 
before the latter gives off a communicating 
branch to the pudendal nerve Sometimes 
it arises together with the communicating 
branch or each strand of the caudal gluteal 
may anse separately before and after the 
origin of the communicating branch (Bosa 
1965) The caudal gluteal nerve supplies 
the gluteobiceps muscle 
The caudal cutaneous femoral nerve usually 
denves its fibers from the ventral branches 
of the second and third sacral nerves with 
an inconstant branch from the first sacral 
Someumes the fibers constituting the nerve 
run separately as they cross the proximal 
part of the pudendal nerve and enter the tex 
ture of the broad sacrotuberal ligament or 
they join the pudendal nerve course together 
for a short stretch in the ligament and then 
leave either as a single nerve or in a succes 
sion of two to three branches supplying the 


U( UHI 16-26 lanlumbar glo 
teal and femoral regions of boar left 
aide schematic 

5 Lateral cutaneous femora! n f era 
nUl cl u leal a 7 branch of C to cluieut 
profun I s B Isohutlr n 0 caudal flu 
lea! n 10 communicating trranch from 
ischiatie n to pudendal n 1 1 pudendal 
n 12 caudal cuuneou* femoral a 13 
branch to coccy ecus 14 branch of 11 lo 
i roccnltal tract 13 conllnujtion of 11 
at dorsal n of pent* and middle scrotal 
n If deep perineal n 1 7 superficial 
perineal a IB 10 caudal rectal (hemor 
rt oldalJ n 20 21 22 muscular tranche* 
of l*cl lade n. 23 lateral plantar cutan 
rout tural n <N A \ caudal cuuneou* 
sural n) 21 til U1 n. 25 Tbutar n 
(IS A V common peroneal) A loncis- 
ilmu* II aponeurosis of ot ll<juu* In 
temus abdominis C obliquut rslernu* 
abdominis (cut) D lliacu* F vastus la 
terall* F glulroblceps (cut) C castroc 
nemlui M solrus J semlfendinosus K 
semimembranosus L. retractor penis 
M levainr an! N coccygeus O veslcu 
lar eland P rectus femorls Q gluteus 
profundus H sphincter anl extrmus 
Cy ventral brnnch of caudal n I S S 
ventral branches of sacral nn. I to JV 
(From Bosa and Telly 19f0) 

skin covering the gluteobiceps and semi 
tendinosus muscles This union between the 
caudal cutaneous femoral nerve and the pu 
dcndal nerve takes place before the latter re 
ceivcs the communicating branch from the 
ischiatie (Bosa and Getty 19G9) 

The ischiatie nerve is formed by the ventral 
branches of the fifth and sixth lumbar and 
first and second sacral components of the 
lumbosacral plexus with an occasional con 
tribution from the ventral branches of the 
third and fourth lumbar nerves (Figs 46-27 
and 28) These fibers converge at the level 
of the caudal end of the first sacral segment 
and pass through the greater ischiatie fora 
men It is a flat band lying in the gluteal region 
on the gluteus profundus muscle (Fig 46- 
26) It continues caudally over the gemelli 
quadratus femons and adductor muscles 
In addition to the cranial and caudal gluteal 
nerves the ischiatie nerve gives off the fol 
lowing branches in succession (1) A constant 
communicating branch goes to the pudenda! 
nerve at the caudal limit of the greater ischi 
atic foramen It courses along the dorsal bor 
der of the gluteus profundus muscle passing 
between the internal iliac vessels and thus 
arrives at the lesser ischiatie foramen where 
it joins the pudendal nerve (2) At the lev el of 
the greater trochanter of the femur it releases 
a large muscular branch for the proximal parts 
of the gluteobiceps and semitendinosus (3) 
The caudal cutaneous femoral nervcalsolnner 
vates the skin just above the proximal attach 
ments of the gluteobiceps and semitendin 
osus after coursing between them (caudal 
ciumal nerves) (4) From its ventral aspect 
It gives off branches to the gemelli and quad 



46— PORCINE NERVOUS SYSTEM 


1393 


ratus femoris muscles. (5) Slightly distal, 
in the thigh region, it gives off a large mus- 
cular branch for the gluteobiceps (middle 
part), semitendinosus semimembranosus, 
pectineus and adductor. (6) Another mus- 
cular branch is given off for the distal part 
of the gluteobiceps. Some of its fibers, after 
piercing through this muscle, ramify in the 



FIGURE 46-2T. Nene* or distal part of right pel- 
vic limb of pig; dorsal view, a choreatic. 

1. Superficial fibular (peroneal) n.; 1\ medial branch; 2, 
dorsal common (pedal) (fitful n. IV; S, medial (axial) dor- 
sal (pedal) digital n. IV: 6, deep fibular (peroneal) n. (dor- 
sal metatarsal n. Ill below ur»u(); 7. dorsal common 
(pedil) (fitful n. H; 9, medial (axial) dorsal (pedal) dltf ul 
n 111; II, saphenous n.; 12. lateral (ahudal) dorsal (pedal) 
digital n, V; 13. dorsal proper (pedal) digital n«- IV and V; 
14. medial (abetxUl) dorsal (pedal) ditf tal n, H: 15. dorsal 
proper (pedal) ditful nn. II and III. (From Ghoshal and 
Getty, 1967b,) 



FIGURE 46-28. Nerves of distal part of right pel- 
vic limb of pig; plantar view, schematic. 

10, Lateral plantar cutaneous aural n. (NAV: caudal cu- 
taneous sural n.); 20, Ubial n.; 21, medial plantar n.; 21', 
media] branch; 21 ', lateral branch; 22, plantar common 
digital it. II; 24, plantar proper (axial) digital n. Ill; 25, lat- 
eral plantar n.; 26, deep branch; 27, plantar common digi- 
tal n. Ill; 28, plantar proper (axial) digital n. IV; 29, medial 
(abaxial) plantar digital n. II; 30. plantar proper digital nn. 
II and III; 31, plantar common digital n. IV; 32, com- 
municating branch; 33, lateral (abaxial) plantar digital n. 
V; 34, plantar proper digital nn. IV and V. (From Choshal 
and Getty, 1967b.) 


fascia and skin on the lateral aspect of the 
thigh. The apparent division of the ischiatic, 
into fibular (common peroneal) and tibia} 
nerves usually occurs near the middle of the 
thigh or slightly distal to it. 

Tlte fibular nerve passes distocnmially 
beneath the tibia] part of the gluteobiceps 
and lies on the lateral head of the gastroe- 



1394 


PORCINE 


nemius Close to the lateral tibial condyle 
it pierces the soleus muscle and gives a 
branch to the extensor digitorum lateralis 
muscle It courses further between the fibu 
Ians longus and the extensor digitorum later 
alls In the neighborhood of the lateral tibial 
condyle the fibular nerve divides into super 
ficial and deep branches The superficial fibu- 
lar nerve, relatively the stronger of the two, 
descends somewhat superficially between 
the fibu Ians longus and extensor digitorum 
lateralis to the middle of the leg and sub- 
sequently crosses the deep face of the tendon 
of the former muscle The superficial fibular 
nerve detaches the medial branch on the dor 
sal aspect of the tarsus which, after joining 
the lateral branch of the saphenous, contin 
ues distally as the dorsal common (pedal) 
digital nerve II The latter divides into dorsal 
proper (pedal) digital nenes II and IIL • 
According to the N A V (1968) and Beer 
(1968), the medial (abaxial) dorsal (pedal) 
digital nene II may anse from the super 
ficial fibular instead of the saphenous nerve 
as descnbed previously On the dorsal aspect 
of the tarsometatarsal articulation, between 
the proximal and distal extensor retinacula, 
the superficial fibular divides into the medial 
and lateral branches (Fig 46-27) The lateral 
branch, immediately distal to the tarsus, de 
taches the lateral (abaxial) dorsal (pedal) 
digital nerve V and continues further as the 
dorsal common (pedal) digital nerve IV, which 
finally terminates as the dorsal proper (pedal) 
digital nerves IV and V The medial branch 
descends as the dorsal common (pedal) digi- 
tal nerve III which, near the metatarso- 
phalangeal (fetlock) joint, receives a com- 
municating branch from the dorsal meta- 
tKn.1 1U ffcvAax Vt 

divides into dorsal (axial) proper (pedal) 
digital nerves 111 and IV A single trunk, 
forming the dorsal common (pedal) digital 
nerve III, may be absent, and in that case the 
medial (axial) dorsal (pedal) digital nerve IV 
arises from the lateral branch while the 
medial (axial) dorsal (pedal) digital nerve III 
is the continuation of the medial branch of 
the superficial fibular nerve (Ghoshal and 
Getty, 1968a) 

Close to its origin, the deep fibular nerve 
gives off several muscular branches m a 
variable manner to innervate the fibulafis 
longus, fibulans tertius, extensor digitorum 
longus (including the extensor digid III) and 
tibialis cramahs It continues distally, at first 
alongside the extensor digiti I longus, and 
later crosses its deep aspect and innervates it 
It descends along the dorsal surface of the 
tarsus under the proximal extensor re tin 
aculum and appears between the tendons of 
the fibulans tertius and extensor digitorum 
longus (Fig 46-27) It courses deep to the 


extensor digitorum brevis muscle and, near 
the middle of the metatarsus, divides into two 
branches The slender medial branch ramifies 
within the preceding muscle, while the lateral 
branch (dorsal metatarsal nerve III) con 
tinues distally and, near the metatarso- 
phalangeal joints, gives off a communicating 
branch to the dorsal common (pedal) digital 
nerve III or a communicating branch to each 
of the medial (axial) dorsal (pedal) distal 
nerves III and IV, respectively According to 
Beer (1968), the variability of the branches 
of the deep fibular nerve shows that the 
fibular branch coursing inside the third ri>eta- 
tarsal space supplies both principal digits 
The tibial nerve, following its separation 
from the fibular nerve, extends distally 
through the popliteal region, somewhat 
medial to the popliteal lymph nodes In gen 
eral, it innervates the extensors of the tarsus 
and the flexors of the digits It also furnishes 
the popliteus muscle It descends obliquely 
along the caudal surface of the leg, being 
cranial to the common calcaneal tendon At a 
variable level close to the calcaneal tuber it 
divides into medial and lateral plantar nerves 
and exchanges fibers between them (Fig- 
46-28) 

The lateral plantar cutaneous sural nerve 
(caudal cutaneous sural nerve) frequently 
arises from the fibular nerve and sometimes 
directly from the ischiatic nerve close to Its 
terminal divisions (Ghoshal and Getty, 19t>7b), 
according to Schneider and Zintzsch (1062), 
it is given off by the tibial nerve It continues 
along the caudal aspect of the lateral he?d of 
the gastrocnemius between the gluteobiceps 
and semimembranosus muscles It descends 
farther along the lateral face of the lateral 
Vieai of the gastrocnemius and, cranial to the 
common calcaneal tendon, appears super 
ficially about the middle of the leg It inner 
vates the fascia and skin on the lateral aspect 
of the tarsus and, to a variable extent, of the 
metatarsus, with occasional twigs to the 
gastrocnemius muscle (Fig 46-28) 

The medial plantar nerve of the tibial de- 
scends along the medial aspect of the superfi 
cial digital flexor tendon and, slightly projomal 
to the metatarsophalangeal joint of the third 
digit, it divides into a medial and, lateral 
branch. The medial branch, near the jneta 
tarsophalan geal joint, gives off the medial 
(abaxial) plantar digital nerve II and continues 
as the plantar common digital nerve II The 
latter soon divides into plantar proper digital 
nerves II and III The lateral branch, after 
giving off twigs to the fascia and skin on the 
plantar side of the metatarsus, detaches a 
communicating branch which joins the 
medial branch of the lateral plantar perve 
(Ghoshal and Getty, 1967b) or the plantar 
common digital nerve IV proximal to the jneta 



46 -PORCINE NERVOUS SYSTEM 


1395 


tarsophalangeal joint Following the origin 
of the communicating branch it continues as 
the plantar common digital ner\e III, which 
later divides into plantar (axial) proper digi- 
tal nerves HI and IV The plantar (axial) 
proper digital nerves of the mam digits com 
mumcate with the corresponding dorsal 
nerves through the mterdigital spaces 
Tile lateral plantar nerve passes obliquely 
under the long plantar ligament of the tarsus 
and descends along the lateral face of the 
superficial digital flexor tendon Slightly distal 
to the tarsus it releases the deep branch to 
ramify within the mterossei muscles, there 
after it gives off the lateral (abaxial) plantar 
digital nerve V and continues farther as the 
plantar common digital nerve IV The latter, 
slightly proximal to the metatarsophalangeal 
joint, divides into plantar proper digital nerves 
IV andV As already mentioned, the commum 
eating branch of the medial plantar nerve 
loins the medial branch of the plantar com 
mon digital nerve IV or the nerve itself, 
depending on the level of the latter’s terminal 
branching within the metatarsal region 

Sacral Nerves 

Tile sacral nerves comprise four pairs They 
anse from the terminal part of the spinal cord, 
extending from the cranial border of the sixth 
lumbar vertebra to the cranial third of the 
second sacral vertebra, and are divided into 
the dorsal and ventral branches Each dorsal 
branch, in turn, divides into a medial and 
lateral branch the medial branch being mus 
cular The lateral branches terminate as 
cutaneous nerves over the gluteal region, 
except the last sacral, and are called the mid- 
dle clumal nerves The ventral branches of 
the fifth lumbar through the fourth sacral 
nerves course to the pelvic kmb and the 
penneum 

The pudendal nene frequently derives its 
fibers from the ventral branches of the sec 
ond and third sacral nerves, with an inconstant 
contribution from the first or fourth sacral 
(Fig 46-35) It courses along the medial 
aspect of the broad sacrotuberal Ligament, 
being covered by the intrapelvic part of the 
obturatonus extemus muscle The nerve 
enters the texture of the ligament and tra 
verses it for a short distance, leaving it near 
the lesser ischiatic foramen, where it joins 
the communicating branch from the ischiatic 
nerve Inside the pelvic cavity it gives off a 
branch which, after coursing along the edge 
of the sacrocaudales ventrales muscles, in 
nervates the coccygeus muscle At the level 
of the lesser ischiatic foramen the pudendal 
nerve gives off the superficial and deep 


perineal nerves, the dorsal nerve of the penis 
or clitoris, the caudal scrotal or mammary 
branch and the labial nerve innervating the 
various structures in the penneum, including 
the scrotum in the male and the mammary 
glands in the female Near the ischiatic arch 
the pudendal nefve gives off two branches, 
one of them Innervates the ischiocavemosus 
muscle, while the other, after passing along 
the side of the sigmoid flexure, reaches the 
interscrotal fascia and ramifies there as the 
middle scrotal nene The proximal and distal 
cutaneous branches of the pudendal nerve 
innervate approximately the same area as the 
caudal cutaneous femoral nerve in other 
species In addition, the distal cutaneous 
branch supplies the superficial penneal nerve 
The perineal nenesare variable in number 
They may anse separately or by a common 
trunk from the pudendal and are arranged 
into superficial and deep groups, the former 
innervates the skin of the penneum, while 
the deep group is distnbuted m the stnated 
musculature of this region The superficial 
perineal ner\e anses together with the deep 
penneal nerve Following a short course be- 
yond the ischiatic tuber it separates and 
pierces the tuberous attachment of the broad 
sacrotuberal ligament Inside the ischiorectal 
fossa it divides into two branches the labial 
nerve courses toward the anus and is distnb 
uted in the skin and upper part of the vulva, 
the other, larger, branch continues over the is- 
chiatic end of the semimembranosus and sup 
plies the skin here and below the vulva in the 
female and that of the caudal surface of the 
scrotum in the male These nerves are called 
labial nerves in the female and caudal scrotal 
nerves m the male The deep perineal nerve 
may anse together with the superficial 
penneal, as previously mentioned, and inner 
vates the sphincter am extemus, levator am, 
constrictor vulvae, ischiocavemosus and 
bulbospongiosus (bulbocavemosus) muscles 
These muscles also receive small branches 
directly from the pudendal, all of which are 
designated as the deep penneal group of 
nerves A branch anses, in both sexes, from 
the pudendal nerve, which frequently ex 
tends along the urogenital tract and seems to 
contnbute to the formation of the pelvic 
plexus This branch innervated the urethralis 
and constnctor vestibuh muscles 
The caudal rectal nerve frequently anses 
trom the ventral branch of the fourth sacral 
nerve, with an inconstant branch from the 
third sacral It courses caudally, being 
covered by the sacrocaudales ventrales mus 
cles, and ends in the sphincter ani extemus 
and levator am muscles In some cases the 
middle rectal nerve from the ventral branch 
of the third sacral or from the pudendal nerve 



139G 



roRcisr. 

Into a medial and latrral branch In th** f*r»» 
xhrrr at four juirt The ventral branches of 
ihc first rautUI nerve >oln that is? the fourth 
wrral Thu course* taudaJly and constitutes 
ihr ventral randsl pleiot by the of fho 

ventrolateral branches {>ig Itoth the 

dorsal end ventral caudal fumhh 

the muvotihuurr. fascia and *Un on the rr 
spectlve aide to the tlf* of the tail 


bibliography 

t-M* p »»** rw s a ~. rnMf««i s*** *.*♦«* u ». 

Itea liMlumakk 

Im 1 M IM W .* < *..«< > ' iwi <4 ft* * . ■ ** ■« •* 

mftsm* *f ft. «— w H K' IW. »— •«« 


| M*4 «V TT 

» c.Mit !«*«« mi ft*.— mu *iJ «— a |i 

— ») M •< sft t IWt (m. JftMr. I — 



(Frntn CftrvJhl arwt Cctty |VAc ) 


gives off a branch to the caudal rectal nerve 
and it distributed, either separately or to- 
gether, in the structures already mentioned 

Caudal Nerves 

The caudal nerves vary between four and 
eight pairs, although tlx pairs are frequently 
present (Candhi and Getty, I9G9c) They 
emerge through the inters ertebral foramina 
caudal to the corresponding vertebrae. Im- 
mediately after their emergence each divides 
into dorsal and ventral branches. The dorsal 
branches course dorsally over the transverse 
processes of the succeeding vertebrae and the 
intertransversaril dorsales caudae muscles 
The dorsal branches of the first three or four 
pairs divide distinctly into medial and lateral 
branches The dorsal branch of the first cau- 
dal nerve Joins that of the fourth sacral The 
dorsolateral branches Join each other to form 
a dorsal esudsl plesus The ventral branches 
are stronger than the dorsal, and each divides 


4R C*"7 |1 

ft rw r 
*J MU 

Lmiu a S,**M C— I****. C— •— « •< ft* «— » •* 

eft* « ■ ** r»« Mi HHU h*«wm *» A* — 

M II Cftft— — l4 »- ft—* ftf-ft »M« t*M 

J W M 1 V« 

IW-. « l,**4 X t***. !«***• C* — ■ *»— M A* >— ft rf 

(ft* «.«.■». ft >M> ftftft Wi "/— • ** ft* •*— * ft — ft 

r*t m t — *f ft* v— »*/ •*< 

.. — ft ft— ft— J •*! ft* > 1-41 
U*U H C iw» * .—*—7*. ftM0M*tv*l e«*. ftl Aft 

■/ a. ft i ■ ■ ■ * » 1 ftwftx ini*, r.fv*. i.ftM 

N.uui ran rw— i— 1>* 

IUU K t Mil C— 1 ■*» I 

iMftTft- m i— ft** i *. ft- n rs *» 

C WW t H C.ftftllL C*71 )«**\ Ummmi vf Aft ft*« «M M 
•# (ft* 4 — «I r<< rift* XXI 1 , ft— fttwfti l< 4 .» J Aft** 
h«ft»< iti m 

C *»« *■« ! ft C. *4 a C—*.. |Mft. A .MfHtftH ftftftQ Ui p iW 



SIS 


•<ft« r«, 


CftM.AI. r l*« I*. S.O~« ft., |*U* Clftftt 

>**•« t»*« InMtwwtwK SMtftft Cr***ft. 

MftOlM, J *' I*** ft *••*»> *U»* ft * MWh «4 Ifcft 

”‘|* 1 •# r*«> uwii i Sfttwu- o*u/ c.r'A* 

1.0* ».»>**/ 1 rvll TVmm. »— Ift*. tr, ft — 

Kftto**. j »t a c— t W ft c. C-WM1 im a 

** *** S » *»«^«l ftAftlllftkwtaJ H*.», »> I.HNU. ft**. 1 . 
It*l A.f *•. M *4 k*«| |*. Iw. J W .IllUI 

Menu*, t **4 t »— 4-a. t*» tMMU, «*«5*Wft 4*. 

u«— IwifA » ftra. lOMt. ftt fill 

VmnMfti im« ft J AHMHtM *f 

•MM. VlMftft. ft. MTU 

„ . . 1 «“>4****ri« Am 

t.^ftO* |*,| t)iH iMnwrtUwtttUMM 

*<tm*ra 11 l»» V.rtUfc S —ft. IwvMui tin A. Nmt* 
,u *4 0*4 *«<" I — S— \«ftW «4 
lbnt*ffftftw> M 4*m Hn«kn n* ft*u f M» 

ftknr, II— s.«* r> nr v«u« — 

Kail hi** 

S/WtA, j. Mi l r/M.ftk »sei Dft t— .MftWw ft ft- 
Utf*ftUl»n *n Scfc ftftt ft ftA IM Vr. XI .... t. 
iMftin. K aftt l tl Cnuiuft jui ft 

AMm.lt 4th *4 rhilfti.f»hu ft a t 

ro<iftk>7ft>M.o. r. AttftftftM.ftiit cr.« 

Bft*m * lUMWh 4*t ttrtWfthraftM. Aftluu ftn II.Mlftt. 
11*4 S**tm. »pn*«r* V*n,g 


7 «C tb. Cum ..w 



46 -PORCINE NERVOUS SYSTEM 

AUTONOMIC NERVOUS SYSTEM 


1397 


The cranial portion of the autonomic 
nervous system is discussed with the cranial 
nerves m this chapter and in Chapter 13. 

CERVICAL AND THORACIC 
AUTONOMIC INNERVATION 

by J. S. McKibben 

Cervical and thoracic sympathetic chain 
ganglia and the tenth cranial nerve and its 
branches supply autonomic innervation to 
cervical, thoracic, and abdominal structures. 

Sympathetic Part 

Ganglia of the cervical and thoracic parts 
of the sympathetic trunk serve as the ongin 


for postganglionic sympathetic fibers passing 
to cervical and thoracic structures. 

CERVICAL PART 

The cervical sympathetic trunk in the pig 
extends from the cervico thoracic or caudal 
cervical ganglion to the cranial cervical gan- 
glion, through the ansa subclavia and vago- 
sympathetic trunk. Cervical ganglia in the 
the pig include the vertebral, intermediate, 
middle cervical, and cranial cervical ganglia. 
In many pigs the first thoracic and caudal 
cervical ganglia do not fuse and the caudal 
cervical ganglion may be .considered as part 
of the cervical sympathetic trunk. 

^Vertebral ganglion. On the left side, 
the ansa subclavia (Fig. 46-30/5) usuallyarises 
and returns to the cervico thoracic ganglion as a 
caudal limb only. The vertebral ganglion is. 



FIGURE 46-30. Cardiac nenren and related ganglia of pig; left lateral view. 


I, Ramui communicant 5. aympatbetie trunk. 3b-h. aecond through eighth thoracic ganglia, 4, cervicothoracle eanell 
on, 5, caudal limb of anw tube Lav la, C. cardiac ganglion of left ImcrvatcuUr triangle. 7, Intermediate ganglion 9 middle 
cervical ganglion. 11, vacua n . 2 2'. left recurrent Urrn£«l n.; 13. thoracic cardiac ft; 14. cranial and 14*. caud ©ventral 
cervico* horactc cardiac nrt. 2G-j» ertcbral n.; 17. Intermediate cardiac n . 19. middle cervical cardiac n_. 21. cranial and 
at .taudal vagal cardiac nit. i2. recurrent cardiac rt. 24a. eighth cervical .pirul rv. 25a. firat iboraric 2™ 


varr’dar n. Aih first through eighth riba. B. longut coilJ m , C, evophagu* D. intercostal a" • 
V*®”* htoeephal ic trunk. G*. left subclavian jl; II. coatocereical a.. K. vertebral a.; L, deep crrvl 


; tV , Intercostal r ; E. aorta. 


L. deep cervical a.; M'. ctmocendcover 


lebraj e ♦ N . left common carotid O', lefi vena uygoe. f>. cranial vena cava. It', right and S . left auricle* T 

*■ BD '- & 



1398 


PORCINE 



FIGURE 46-31 Cardiac nerve* and related j^nglia of pic, right lateral view 


1 hanui* cammunicans 2 sympathetic trunk 3a h, first throu(h eighth thoracic ganglia 4 cervicotboracic ganglion 
5 caudal and 5 cranial limb* of ansa subclavia 7 Intermediate ganglion 8 vertebral ganglion 11 vagusn. 12, right re- 
current laryngeal n. 13 thoracic cardiac n. 14' caudoventral cervicothoracic cardiac n. 16 vertebral n. 17 Intermediate 
cardiac n. 18 caudal vertebral cardiac n. 21 caudal vagal cardiac n. 22 recurrent cardiac n. 23 sympathetic n. to 
phrenic n. 24a, eighth cervical ipinal n. 25a. first thoracic spinal n. Aa-h first through eighth rib* B longu* colli C 
e* Op ha gut E, aorta C* right (ubclavian a. II cmtocervical a. h. vertebral a. M coitocervicovertebral v N* right com- 
mon carotid a. P cranial vena cava Q caudal vena cava R, right atrium R right auricle 7 right ventricle U left ven- 
tricle W trachea X, bronchus Z.lung BB right coronary a. DO coronary tinui EE, thoracic duct FF middle cardiac 
v (From McKibben and Cetty 1969a.) 


therefore, incorporated into the cervico- 
ihoracic or the caudal cervical ganglion on 
this side. The cervical sympathetic trunk (2) 
arises from the combined ganglia and passes 
cramally, independent of the ansa subclavia, 
to join the vagosympathetic trunk. Both limbs 
of the ansa subclavia are generally present on 
the right side (Figs 46-31/5 and 5 ) The right 
vertebral ganglion (8) hes at the cramoventral 
extent of these limbs and about 10 mm cranial 
to the cemcothoiacic ganglion just cramo- 
medial to the vertebral artery (K) The cervical 
sympathetic trunk continues cramally from 
the vertebral ganglion in the vagosympathetic 
trunk. The nght vertebral ganglion averages 
10 mm craniocaudally, 3 mm dorsoventrally, 
and 2 mm mediolaterally Nerves from the 
nght vertebral ganglion pass to the phrenic 
nerve, brachiocephalic trunk, subclavian 
artery and its branches cranial vena cava. 


nght vagus nerve, heart and lungs A nght 
vertebral cardiac nerve (Fig. 46-31/180 
courses caudally, ventral to the subclavian 
artery to the nght intermediate ganglion (7) 
Its fibers contmue with the nght intermediate 
cardiac nerves to the pretracheal portion of 
the cardiac plexus, along the nght coronary 
artery, descending and circumflex branches 
of the left coronary artery on the left side of 
the heart and between the cranial and caudal 
venae cavae Another nght vertebral cardiac 
nerve may pass independently to the pre 
tracheal portion of the cardiac plexus and 
onto the lateral wall of the nght atrium. 

Intermediate ganglion An Interme 
diate ganglion is located, between other 
named ganglia, on the caudal limb of the ansa 
subclavia near the caudoventral border of the 
subclavian artery, similar in location to that 
of the cat Although constant in occurrence 



FIGURE 46-32. Cardiac innervation of pig; dorsal vier. The sympathetic tranks and vagi are reflected 

laterally. 

1, Ramus comm unicans, 2, sympathetic trunk, 3a h. first through eighth thoracic ganglia, 4. cervicothoracic ganglion, 
5. caudal and S’, cranial limbs of ansa tubclavla, 6. cardiac ganglion of left intervascular triangle, 7, intermediate gangli- 
on, B. vertebral ganglion. 9, middle cervical ganglion, 10, cranial cervical ganglion, 11. vagus n , 12 , tight and 12% left re- 
current laryngeal rm-, 13, thoracic cardiac n.. 14, cranial and 14". caudoventral cervicothoracic cardiac nn ; 16, vertebral 
n ; 17, intermediate cardiac n.; 18% caudal vertebral cardiac n., 19, middle cervical cardiac n.; 21, cranial and 21% caudal 
Vagal cardiac nn ; 22, recurrent cardiac n.; 24a g. eighth through second cervical spinal nn.. 25a h. first through eighth 
thoracic spinal nn.; 26. vascular n.; 2B. cardiac plexus. 29, distal (nodose) ganglion of vagus n , E, aorta, F, brachiocepha- 
lic trunk, C% left subclavian a., 0% left vena azygos. P, cranial vena cava, Q. caudal vena cava, R, right atrium, R% right 
auricle, S% left auricle, T, right ventricle, U. left ventricle, Y, pulmonary trunk, BB, right coronary a.; BB% descending 
branch of left coronary a. (From McKlbben and Getty, 1969a.) 


1399 



PORCINE 


1400 

on the nght ansa it is variable in occurrence 
on the left ansa. 

The nght intermediate ganglion averages 
4 mm cramocaudally, 2 mm dorsoventrally 
and 1 mm mediolaterally Branches pass 
from this ganglion to adjacent blood vessels, 
the lungs and the heart. Branches extend to 
the lungs via branches of cardiac nerves 
Left intermediate cardiac nerves (Fig- 
46-32/17) accompany left cervicothoracic 
cardiac nerves primarily to the cardiac gan 
glion of the left intervascular triangle (6), 
then follow and ramify along the circumflex 
branch of the. left coronary artery caudally 
and on the right side of the heart- 
Right intermediate cardiac nerves (Fig 
46-32/17) receive contributions from the 
right vertebral and cervicothoracic cardiac 
nerves and pass caudally on the cranial vena 
cava. One passes ventrally, to the left of the 
nght auncle, into the coronary groove and Is 
distnbuted along the right coronary artery 
Another nght intermediate cardiac nerve 
passes caudally between the aorta and cranial 
vena cava to the cardiac plexus Its main con 
tmuation follows the cranial edge of the left 
auricle to ramify in the interventricular para 
conal sulcus and area of the coronary sinus 
Other branches ramify between the venae 
cavae onto the right atnal wall 
Middle cervical canclion A ganglion 
located on the left cervical sympathetic trunk 
between the cervicothoracic and cranial 
cervical ganglion may be present (Fig 46- 
32/9) This ganglion, which is not associated 
with the Umbs of the ansa subclavia, may be 
either the middle cervical or an intermediate 
ganglion since the vertebral ganglion Is in 
corporated Into the cervicothoracic ganglion 
(4) on this side. Since It may form into a 
discrete ganglion measuring about 7 mm 
craniocaudally, 3 mm dorsoventrally and 2 mm 
mediolaterally, and Is located similar to the 
middle cervical ganglion of the goat, it will be 
referred to as the middle cervical ganglion. 
Middle cervical cardiac nerves (19) have 
been reported to pass caudally from this gan 
ghon to ramify in the cardiac plexus (McKib- 
ben and Getty, 1969a) A similar ganglion 
has been observed in one pig on the right side 
(Engel, 1974) 

Cranial cervical canclion The cranial 
cervical ganglion lies at the cranial end of the 
sympathetic trunk, caudomedial to the jugu 
lar process of the occipital bone and ventral 
to the tympanic bulla about 1 cm dorsal to 
the area of the distal gan ghon of the vagus 
nerve In shoats (young pigs) it measures 
about 10 mm x 4 mm x 3 mm No cardiac 
nerves have been demonstrated to arise from 
this ganghon It contributes branches to 
cranial and cervical structures similar to the 
branches of this ganglion in the horse 


THORACIC PART 

The thoracic sympathetic trunk lies bi 
laterally ventral to the costovertebral joints 
from the cervicothoracic ganglion to the 
diaphragm When the cervicothoracic gan 
glion is not fused, the thoracic sympathetic 
trunk's cranial extent is the first thoracic 
ganglion. 

Cejwicotiioracic canclion This gan 
glion generally extends from just cranial to 
the first rib to the first intercostal space on the 
ventrolateral surface of the Iongus colli mus 
cle (Figs 46-30 and 31/4) It is often partially 
di vid.ed by the vertebral artery on the left side 
The cervicothoracic ganglion is composed of 
at least part of the first thoracic and caudal cer 
vical ganglion, but on the left side also usually 
includes the vertebral ganglion When the 
first thoracic and caudal cervical ganglia are 
not completely fused the latter may be united 
with the vertebral ganglion. Dimensions of 
the cervicothoracic ganglion in the shoat 
average 18 mm craniocaudally, 4 mm derrso- 
ventrally and 2 mm mediolaterally Rami 
communlcantes generally extend via the 
vertebral nerve to the seventh through sec 
ond cervical 6plnal nerves (Fig 46-32/29b g) 
(McKibben and Getty, 1969) The ramus to 
the seventh cervical spinal nerve arises from 
the vertebral nerve prior to its entrance into 
the transverse foramen of the sixth cervical 
vertebra. The eighth cervical (24a) and first 
thoracic (25a) rami communlcantes arise 
independently from the cervicothoracic gan 
glion (4) Cervicothoracic nerves together 
with branches from the vertebral ganglion, 
intermediate ganglion and vagus nerve join 
to form a plexus of nerves medial to the sub- 
clavian arteries From this plexus branches 
extend to the thymus, phrenic nerve and 
thyroid gland, as well as along branches of 
the subclavian artery and major branches 
from the cervicothoracic ganglion, and supply 
the bean and lungs. One to four left cervieo-' 
thoracic cardiac nerves (14 ^ pass to the nght 
intermediate ganglion (7) where they join 
nght intermediate cardiac nerves (17) To- 
gether these nerves are distnbuted in the 
cardiac plexus, along the right coronary 
artery, descending and circumflex branches 
of the left coronary artery on the left side of 
the heart and between the venae cavae 

Thoracic ganglia. Thoracic sympathetic 
tnink ganglia (Figs 46-30 and 31/3a h) are 
generally present in each intercostal space 
from the first or second space caudally Each 
measures approximately 3 mm craniocaudal 
ly, 2 mm dorsoventrally and ? mm medio- 
laterally Thoracic nerves pass ventrally from 
thoracic ganglia to the great vessels, esoph 
agus lungs and heart. 

Left thoraeie eardtae nerves (Ffg. 46-30/13) 



46— PORCINE NERVOUS SYSTEM 


1401 


arise from the first through seventh left 
thoracic ganglia Two or three arise from the 
first and second ganglia and pass to the left 
intermediate ganglion, located on the caudal 
limb of the left ansa subclavia. Branches con 
tinue with theleft intermediate cardiac nerves 
to the cardiac ganglion of the left inter 
vascular triangle Here they join thoracic 
cardiac nerves from the left fourth, fifth, 
sixth and occasionally seventh thoracic inter 
costal spaces Some branches bypass the 
cardiac ganglion of the left intervascular tn 
angle Together, left thoracic and inter 
mediate cardiac nerves enter the cardiac 
plexus Most, however, continue from the 
area of the cardiac ganglion along the left 
vena azygos to the coronary sinus Areas sup 
plied include the dorsum of the left auricle, 
ventrum of the left atnum, right and caudal 
portions of the left ventricle and interatrial 
and interventricular septa from the right side 
Right thoracic cardiac nerves (Fig 46-31/13) 
anse from the first and second thoracic gan 
glia They course ventrocranially to the nght 
intermediate ganglion and, together with the 
nght intermediate, vertebral, and cervico 
thoracic cardiac nerves, pass to the heart 
Branches continue through the cardiac 
plexus and along the coronary artenes Areas 
supplied include the cranial and ventral por 
tions of the auricles, nght ventncle, cranial 
and left portions of the left ventncle, and 
interventricular septum from the left side 
Twigs extend also between the venae cavae to 
the lateral nght atnal wall 
The cardiac plexus (Fig 46-32/28) of the 
Pig resembles that of other domestic animals 
The cardiac ganglion of the left intervascular 
tnangle (Fig 46-31/6) resembles that of the 
ox (McKibben and Getty, 1969b), sheep 
(McKibben and Getty, 1969c) and man 
(Mizeres 1963, Hardesty, 1933) Branches 
from the pretracheal portion of the plexus 
pass to subsidiary cardiac plexuses as well 
ns to the bronchi and lungs 
The greater (major) splanchnic nerves anse 
from several ganglia within the thoracic 
cavity and pass caudally in apposition to the 
thoracic sympathetic trunk At the level of 
the last thoracic \ertebra they separate from 
the sympathetic trunk as a much larger nerve 
than the remaining trunk (Ghoshal and 
Getty, 1969) The thoracic sympathetic trunk 
enters the abdominal cavity between the 
psoas minor muscle and vertebral column 
lateral to the crus of the diaphragm and con 
tinues caudally as the thin lumbar s>mpa 
thetic trunk The greater splanchnic nerve 
after passing through the lumbocostal arch, 
•s distributed to the abdominal organs through 
the cehacomtscntenc plexus as described 
on page 1405 Lumbar splanchnic nerves 
ore not clearlj div ided into cranial (lesser or 


minor splanchnic) and caudal groups m their 
contnbu tions to the cehacomesentenc plexus 
(Ghoshal and Getty, 1969) 

Parasympathetic Part 

The vagus nerve contnbu tes paiiasympa 
thetic branches to the neck and thorax of 
the pig 

CERVICAL PART 

The proximal and distal ganglia of the 
vagus are similar in location and function to 
those of the dog The distal ganglion lies 
caudoventral to the cranial cervical gan 
ghon, however, and is not fused to it The 
vagus nerve and sympathetic trunk are held 
in a common connective tissue sheath be 
tween the distal ganglion of the vagus nerve 
and the level of the seventh cervical vertebra. 
No independent third trunk (depressor nerve) 
courses with these nerves m the cranial two 
thirds of the neck, but on the left side one or 
two nerves anse from the vagus m the 
caudal one third of the neck and accompany 
the vagosympathetic trunk toward the heart 
Branches of the cervical vagus include the 
pharyngeal, cranial laryngeal and cranial 
vagal cardiac nerves Twigs also pass to the 
plexus along the medial side of the sub- 
clavian artery 

Pharynceal rranch This branch re 
sembles that of the horse m course and 
distribution 

Cranial laryngeal branch This branch 
also resembles that of the horse in course 
and distnbution (Fig 46-33) 

Cranial vagal cardiac nerves Cranial 
vagal cardiac nerves anse from each vagal 
trunk cranial to the ongm of the recurrent 
laryngeal nerves Those ansing from the left 
vagus (Fig 46-32/21) anse 2 to 3 cm cranial 
to the left subclavian artery, pass caudally, 
ventral to the subclavian artery and over the 
left surface of the aortic arch to the cardiac 
plexus Small right cranial vagal cardiac 
nerves, when present, anse approximately 
2 cm cranial to the ongm of the nght recur 
rent laryngeal nerve, course caudally between 
the thoracic aorta and cranial vena cava, and 
ramify m the pretracheal portion of the cardiac 
plexus 

THORACIC PART 

Each vagus ner\e courses through the 
thoracic cavity similar to those of other 
domestic animals Right and left dorsal and 
ventral vagal branches re form into dorsal 
and ventral vagal trunks on the esophagus 
Other branches include the recurrent laryn 



1402 


PORC1NF 




FIGURE 46-31 Distribution of 
the autonomic nenou* »y»tem in 
the cranial trnrltal region of the 
pitr 

Top right »We bottom left aide 

1 Pharyngeal branch (phtryngo- 
esophageal n) 2.cnnlal branch of 1 
3 caudal branch of 1 4 pharyngeal 
plexus 5 pharyngeal branch of 9 6 
carotid sinus branch 7 ansa errvi 
calls 8 sympathetic n. trunk 9 glos- 
sopharyngeal n. 0 branch to sty 
lopharyngeui 10 vagus n. 11 
accessory a 12 hypoglossal n- 13 
cranial cervical ganglion 14 distal 
ganglion of vagus n 15 crania! 
laryngeal n 15 Internal branch of 
15 15 external branch of 15 17 
branch to crlcothyroideus 18 cranial 
thyroid n 19 ventral branch of first 
cervical n 20 branch between 19 
and 13 21 ventral branch of second 
cervical n. 21 branch between 19 
and 21 22 ventral branch of third 
cervical n 22 branch between 21 
and 22 23 branch to omohyoldeut 
24 dorsal branch of 11 25 ventral 
branch of 1 1 26 external carotid n 
27 branch between 13 and 3 32 
depressor n. 33 Internal carotid n. 
{From Engel 1974 ) 


geal, caudal vagal cardiac, bronchial and 
esophageal nerves 

Recurrent laryn geal nerves The re 
current laryngeal nerves arise and course 
similar to those of other domestic animals 
Branches of this nerve supply the heart, great 
vessels vessels of the carotid sheath lungs 
trachea esophagus, thyroid gland and all the 
intrinsic muscles of the larynx except the 
cncothyroidei muscles Left recurrent 
cardiac nerves (Fig 46-30/22) arise from the 
left recurrent laryngeal nerve (12 ) close to 
the latter’s ongin from the left vagus nerve 
( 11 ) or after the parent trunk has coursed to 


the right side of the aorta The left recurrent 
cardiac ner\es pass ventrally to the pre 
tracheal portion of the cardiac plexus or join 
left caudal vagal cardiac nerves and ac 
company the left vena azygos to the coronary 
groove. Branches are distributed primarily 
to the caudal and right portions of the heart 
Generally one right recurrent cardiac nerve 
(Fig 46-32/22) arises from the right recur 
rent laryngeal nerve withm 5 mm of the lat 
ters origin from the right vagus nerve It 
joins right caudal vagal and cervicothoracic 
cardiac nerves passing to the cardiac plexus 
Continuing branches pass to and ramify 



46 -PORCINE NERVOUS SYSTEM 


1403 


primarily on the lateral wall of the right 
atrium, along the coronary groove on the left 
side, m the interventricular paraconal sulcus, 
and along the right coronary artery 
Caudal \agal cahdiac NERVES Caudal 
vagal cardiac neives anse from each vagus 
caudal to the ongin of the recurrent laryngeal 
nerves Generally three to six left caudal vagal 
cardiac nerves (Fig 46-32/21’) anse within 
4 cm caudal to the ongin of the left recurrent 
laryngeal nerve These nerves pass to a plexus 
on the dorsum of the trachea or directly along 
the left vena azygos to the heart Most of the 
branches entering the plexus on the dorsum 
of the trachea pass to the lungs but two or 
three course cranialiy and accompany 
branches passing with the left vena azygos 
to the caudal and left portions of the coronary 
groove and extend to the interventricular 
subsmuosal sulcus 

A right caudal vagal cardiac nerve (Fig 
46-32/21') joins the nght recurrent and right 
cervicothoracic cardiac nerves and passes 
caudally on the dorsum of the cranial vena 
cava Branches extend between the venae 
cavae onto the nght atnal wall and to the pre 
tracheal portion of the cardiac plexus (28) 
Branches continue through the cardiac plexus 
and ramify along the nght coronary artery and 
the left coronary artery on the left side of the 
heart One or two nght caudal vagal cardiac 
nerves anse from the nght vagus caudal to 
the ongin of the nght apical bronchus They 
course ventrally on either side of the caudal 
vena cava and ramify in the area of the 
coronary sinus and onto the nght atnal wail 
A nght caudal vagal cardiac nerve may arise 
from the vagus between the two loc ltions just 
descnbed and course ventrally to the nght 
pulmonary veins and pretracheal portion of 
the cardiac plexus 

Bronchi \i nerves Left bronchial nerves 
anse with and just caudal to the left caudal 
vagal cardiac nerves and pass ventrally to a 
plexus on the dorsum of the trachea from 
which nerves extend along the bronchi Right 
bronchial nerves pass from the nght vagus 
ner\e caudal to the caudal \agal cardiac 
nerves and extend along the bronchi 
Branches extend from the cardiac plexus to 
the bronchi as bronchial nen es also 

I sophaceal nerves Numerous small 
esophageal nerves anse from the vagi, dorsal 
a nd ventral vagal branches, and dorsal and 
ventral vagal trunks, and pass to the csoph 
agus 


BIBLIOGRAPHY 

1 11 S jf J9'4 A temjufautr matp) clonic iiudr oftlwfTrU 
wumfNi >c- Inner* <»lo i In ihr llohr (h Pts arul Dos \1 S 
** Auburn t mvcw tf Auburn. Atila mi 


Choshtf S G andR Gett) 1969 Postdlaphragmatic disposition of 
the pars sympa thica and major au lonorni" ganglia of the domes 
tic pig (5«s scTofn domesttca) Anat Anz 12a 400-411 
Hardesty I 1933 The nervous system in Morris Human Anatomy 
Edited by C M Jackson 9th ed Philadelphia W R S Hinders 
Co pp 625-1127 

Mchibbc-n J S and ft Getty 1969a Innervation of heart of domes- 
ticated animals Pig Am. J Vet Rts 30 779 789 
McKtbbi>n J S andR. Getty 1969b A study of the cardiac jnnerva 
Hon in domestic animals Cattle Anat Rec IBS 14I-t52 
McKibben J S and R Getty 1969c A comparative studv of the 
cardiac Innen ation in domestic animals Sheep Acta Anat 74 
22S 242 

AUzercs N J J9G3 The cardiac plexus in man Am J Ami 112 
141 151 


ABDOMINAL, PELVIC AND CAUDAL 
AUTONOMIC INNERVATION 

by N G Ghoshal 


ABDOMINAL PART 

The greater (major) splanchnic nen e arises 
from several ganglia inside the thoracic 
cavity During its course it is very closely 
associated with the thoracic segment of the 
sympathetic trunk and frequently exchanges 
fibers with the interganglionic branches of 
the latter It separates distinctly from the 
sympathetic trunk at the level of the fifteenth 
or sixteenth thoracic vertebra, depending on 
the breed The greater splanchnic nerve is 
frequently larger than the postdiaphragmatic 
sympathetic trunk and terminates essentially 
in the adrenal and celiacomesentenc plexuses 

The thoracic sjmpathetic trunk enters the 
abdominal cavity after traversing the Iumbo 
costal arch The abdominal (lumbar) segment 
is fajrly uniform m thickness throughout its 
length, the interganglionic branches are 
single (Fig 46-34) Sometimes intermediate 
ganglia are present in the interganglionic 
branches of the abdominal sympathetic trunk 
(Uchida 1929) 

The elongated, spindle shaped lumbar gan- 
glia usually number six or seven and cor 
respond to the lumbar segments, depending 
on the breed The presence of intermediate 
ganglia in the abdominal sympathetic trunk 
gives the divided appearance of the lumbar 
ganglia 

The communicating branches of the cranial 
lumbar segments are usually split They 
course on either side of the lumbar vessels 
and innervate them After arising from ap 
proximately the middle of the lumbar ganglia 
they course transverse!) and join the spinal 
nerves near the intervertebral foramina The 
oblique communicating branches anse with a 
spinal nerve of one segment and, after 
coursing obliquely caudad over the inter- 
vertebral discs deep to the subiumbar mus 
cks, usually jom the interganghomc branch 



1404 


PORCINE 



FIGURE 46-34 Postdiaphragmatie disposition of the sympathetic part and major autonomic ganglia of pig, 
ventral view 


(From Ch tshal and Getty 1969 ) 



46 — PORCINE NERVOUS SYSTEM 


1405 


of the trank close to the next caudal ganglia 
They contain preganglionic fibers 
1932) They are variably present between the 
last thoracic and first three or four lumbar 
segments Sometimes the intermediate gan- 
glia are present close to the ; ongin * e c0 ™ 

mumcating branches (Uchida, 1929, Botar, 

1932) 

The lumbar splanchnic nenes are not clear 
ly disposed into cranial and caudal groups An 
average of five to ten lumbar splanchnic 
nerves extend from the abdominal sympa 
thetic trank to the visceral ganglia or plexus, 
their caudal limit, going to the caudal mesen 
tenc ganglion, lies at the fourth or fifth 
lumbar ganglion There are more splanchmc 
nerves on the left than on the nght side (Bosa, 
1965, Bosa and Getty, 1969) 

Bosa (1965) describes three lumbar .““If! 

on the nsht side each ot which arises from the lumtor 

ganglion from the interganghonlc part between the sec 
ond and third ganglia and from ihc cranial end of the third 
lumbar ganglion respectively He also describes five > utn 
bar splanchnic nerves on the left side wl, J c * 1 (he 

abdominal sympathetic trunk from one point , 

second and third lumbar ganglia and another between the 
Ihlrd and fourth lumbar ganglia 

The first lumbar splanchnic nerve is usually 
spilt Its cranial branch contnbutes to the 
adrenal plexus, the celiacomesentenc P*ex 
including the celiac and cranial mesenteric 
ganglia and the renal plexus, while its cau 
branch joins the abdominal aortic pie 
(Ghoshal and Getty, 1969) The rest of the 
lumbar splanchnic nerves contribute a 
rectly to the abdominal aortic plexus ana, 
thus, reach the caudal mesenteric plexus ana 
ganglion (Bourdelle and Bressou, 1964, uos, 
1965, Ghoshal and Getty, 1969) Some fibers 
or the lumbar splanchnic nerves bypass tnc 
caudal mesenteric plexus and ganglion ana 
are continued in the hypogastric nerves to 
which the sixth lumbar splanchnic nerv e also 
directly contributes 


Main Autonomic Plexuses ond 
Ganglia of the Abdominal Cavity 

(Fig. 46-35) 

1 The adrenal (suprarenal) plexus is n 
loosely arranged fibrous network between tnc 
deep face of the adrenal gland and the crus 
or Hit. dlaphngm It derives fibers from the 
srcalcr splanchnic nerve, the filaments from 
tin. intergangllonic branches between tnensi 
two thoracic and the last thoracic and lirsi 
lumbar ganglia and the first lumbar sptanen 
*ttc nerve In addition, several short, out 
Wrong branches extend from the celiac Ran 
Rlion 

2. Tile ceUaromescnterir plexus appears as a 
oenvt fihmus network surrounding IM- 
°rfUns of the cel Lac and cranial mesenteric 


arteries The celiac and cranial mesenteric 
ganglia are enmeshed in the cehacomesen 
tenc plexus The paired celiac ganglia lie on 
either side somewhat caudal to the origin of 
the celiac artery, while the apparently single 
cranial mesenteric ganglion lies at the origin 
of the corresponding artery On the nght side, 
both the celiac and cranial mesentenc gan 
eha are intimately fused with each other The 
celiacomesentenc plexus and celiac and 
cranial mesentenc ganglia receive contn 
butions from the greater splanchnic nerve, 
the filaments from the interganghonlc 
branches between the last two thoracic and 
the last thoracic and first lumbar ganglia, and 
the first lumbar splanchnic nerve The pre 
ganglionic parasympathetic fibers reach the 
celiacomesentenc plexus via the dorsal vagal 

3 The aorticorcnal ganglia are closely re 
lated to the celiacomesentenc plexus and the 
celiac and cranial mesentenc ganglia, the 
nght one being vanably fused with the 
former They denve fibers from the celiaco- 
mesentenc plexus, the celiac and cranial 
mesentenc ganglia the thoracic splanchmcs 
and the first lumbar splanchnic nerve 

4 The renal plexus is a loosely arranged, but 
extensive, fibrous network which denves 
fibers chiefly from the celiac and aorticorcnal 
ganglia and from the first lumbar splanchnic 
nerve The visceral branches follow the renal 

** 5 ^ The testicular plexus and ganglion are 
frequently fused to a vanable extent with the 
caudal mesentenc plexus and ganglion, thus 
constituting a thick mass of nervous elements 
around the origins of the corresponding 
artenes This fusion may result between the 
fifth and sixth lumbar vertebrae Sometimes 
separate testicular and caudal mesentenc 
ganglia are seen (Bosa 1965) The testicular 
plexus, in a variable manner, receives fibers 
from the first to fifth lumbar splanchnic 
nerves v la the abdominal aortic plexus The 
visceral branches accompany the testicular 
artery to the testis and epididymis 

A few splanchnic nerve* after sciMratinc from the 
ventral branches or some lumbar spina! nerves close to the 
Intervertebral rnnmlna poshly a, *° contribute to the 
testicular plexus via the caudal mesenteric plexus and 
Rincllon will out trav mine the abdominal sriement or the 
*ympatheilc trunk 

5b The ovunnn plexus in the female is the 
homologue of the preceding It is present 
anmnd the origin of the ov iriui artery It is 
almost identic ll with the preceding In respect 
to partial fusion with the caudal mesentenc 
plexus and ganglion formation .and dlstri 
bution of its fiber* to the ovary and oviduct 

6 The caudal mesenteric plexus and gan 
rlion are located around the origin of the 
caudal mesentenc artery between the fifth 



1406 


PORCINE 



FIGURE 46-35. Postdiaphragmatie disposition of the sympathetic part and major autonomic ganglia of pig; 
ventral view 


(From Ghoshal and Cetty 1969 ) 



46 — PORCINE NERVOUS SYSTEM 


1407 



FIGURE 46-36. Sympathetic trunks and their relationship to the pudendal and pelvic nerves of the pig; lat- 
eral view. 


1, Greater splanchnic n . 2. sympathetic trunks (right and left), 3, abdominal aortic plexus; 4. cranial branch of caudal 
mesentenc plexus which accompanies left colic a., 5, testicular n of testicular plexus (formerly internal spermatic), 6, 
testicular ganglion, 7, caudal mesenteric ganglion, 8, caudal branch of caudal mesenteric plexus which accompanies cra- 
nial rectal a.; 9, right hypogastnc n.; 10, first sacral ganglion, 11, pelvic nn , 12. pudendal n , 13, communicating branch 
from Ischiatic to pudendal n . 14, branches from pelvic plexus to retractor penis m and to rectum, 15, common nerve 
trunk for superficial and deep perineal nn., 16, branch of 12 to urogenital tract, 17. superficial penneal n giving origin to 
caudal scrotal n ; 18, middle scrotal n from 12, 19, dorsal n of penis (continuation of 12), 20. branch of 19 to distal part of 
retractor penis m.; 21, deferential n , A, ureter, B, urinary bladder, C, ductus deferens, D, vesicular gland, E, bul- 
bourethral gland, F, rectum, G, retractor perns; H, sphincter ani extemus, J, testis, K, cremaster (extemus), M, 
Ischiocavemosus, N, penJs, O, preputial diverticulum, Cy,-Cy„ caudal vertebrae, L,-L«, lumbar vertebrae, S,-S«, sacral 
vertebrae, Th, last two thoracic vertebrae (From Bosa and Getty, 1969 ) 


and sixth lumbar vertebrae. The caudal 
mesenteric plexus is variably formed by the 
convergence of the first to fifth lumbar 
splanchnic nerves via the abdominal aortic 
plexus. In addition, a few splanchnic nerves, 
after separating from the ventral branches 
of a few lumbar spinal nerves near the 
intervertebral foramina, contribute to the 
caudal mesenteric plexus and ganglion 
without passing through the abdominal 
sympathetic trunk. As mentioned previously, 
the caudal mesenteric plexus and ganglion 
are more or less fused with the testicular 
or ovarian plexus and ganglion. The vis- 
ceral branches course with the branches of 
the caudal mesenteric artery for peripheral 
distribution. The right and left hypogastric 
nerves arise primarily from the caudal 
mesenteric plexus and ganglion and continue 
in the pelvic cavity. On their course they 
receive some fibers from the abdominal aortic 
plexus, bypassing the caudal mesenteric 
plexus and ganglion, and the sixth lumbar 
splanchnic nerve. 


7. The abdominal aortic plexus is related to 
the ventrolateral aspect of the abdominal 
aorta. The portion of this plexus extending be- 
tween the celiacomesenteric and caudal 
mesenteric plexuses and ganglia is called the 
intermesenteric plexus. It receives contri- 
butions from the right and left celiac ganglia, 
aorticorenal ganglia, variably from the first 
to fifth lumbar splanchnics and perhaps also 
the preganglionic parasympathetic fibers 
from the dorsal vagal trunks by way of the 
celiacomesenteric plexus and celiac and 
cranial mesenteric ganglia. Sometimes a 
separate testicular ganglion, occurring on 
each side of the origin of the corresponding 
artery, is enmeshed m the abdominal aortic 
plexus (Bosa, 1965). 

PELVIC PART 

The pehic (sacral) segment of the sympa- 
thetic trunk gradually diminishes in thick- 
ness and tends to converge caudally. It 
courses along the pelvic surface of the 


1408 


PORCINE 


sacrum, medial to the pelvic sacral foramina, 
accompanying the median sacral artery 
The sacral ganglia number four on each 
side and are segmentally arranged The first 
two ganglia are fairly large and triangular, 
the rest are very small and somewhat spindle 
shaped Sometimes the first and second sacral 
ganglia are fused, having a club-shaped ap- 
pearance 

The communicating branches arise regularly 
from the external surfaces of the sacral gan 
g ha. They are usually single and short After 
coursing obliquely caudad they join the cor 
responding spinal nerves near their emer 
gence from the pelvic sacral foramina. 

Occasionally the transverse and vascular 
branches originate from the internal aspects 
of the sacral ganglia within certain sacral seg 
ments The delicate vascular branches m 
nervate the neighboring vessels 


Mam Autonomic Plexus and 
Ganglia of the Pelvic Cavity 
The pelvic plexus is an extensive fibrous 
network on the ventrolateral aspect of the 
rectogemtal pouch The ganglionic cells are 
scattered throughout the plexus The pelvic 
plexus derives fibers essentially from the 
second and third sacral segments via the 
pelvic nerves (Bosa, 1965 Bosa and Getty 
1969, Ghoshal and Getty, 1969) which pre 
dominantly contain the preganglionic para 
sympathetic fibers 

Bosa (1965) and Bosa and Celty (1969) describe the 
pelvic splanchnic nerves as sometimes arising from the 
first and second sacral segments. 

In addition the right and left hypogastric 
nerves, arising mainly from the caudal 
mesenteric plexus and ganglion together with 
fibers from the abdominal aortic plexus and 
the sixth lumbar splanchnic nerve contribute 
sympathetic fibers to the peine plexus and 
ganglia. Through secondary peripheral 
plexuses the pelvic plexus innervates all 
other pelvic organs 


CAUDAl PART 

The caudal (coccygeal) segment of the 
sympathetic trunk is very slender and is dif 
ficult to trace beyond the ninth caudal 
\ ertebra It courses caudally along the median 
caudal artery From the middle of the fourth 
caudal vertebra it is very small and difficult to 
separate from its fellow of the opposite side 
The caudal sympathetic trunk seems to unite 
and split at various places 


The caudal sympathetic trunks axe sepa 
rated from each other inside the cranial seg 
ments which, however, become single beyond 
the impar ganglion (when present), or within 
the caudal segments 

The caudal ganglia are extremely small and 
are not always present They vary in size and 
are grossly seen only in the cranial three seg 
ments on either side of the accompanying 
median caudal artery The fourth caudal gan 
glion is apparently single where complete 
convergence of both caudal sympathetic 
trunks occurs This constitutes the impar gan 
glion (v Schumacher, 1905, Botar, 1932, 
Ghoshal and Getty, 1969), although it may 
occur as well at the third caudal ganglion 
(Botar, 1932) Sometimes complete fusion of 
the caudal ganglia is not seen and, therefore, 
the constant occurrence of an impar ganglion 
is doubtful (Bosa 1965) 

The communicating branches arise regu 
larly within each caudal segment Inside the 
cranial segments they anse from the caudal 
ganglia and join the respective spinal nerves 
before the latter form the ventral caudal 
plexus In the absence of a caudal ganglion, 
the communicating branches sometimes anse 
slightly further craniad and, after coursing a 
short distance with the caudal sympathetic 
trunk they change their course and join the 
caudal nerves (Botar 1932) Within the caudal 
segments the communicating branches anse 
from the caudal ganglia or from the single 
caudal sympathetic trunk Frequently they 
course transversely or obliquely caudad and, 
on reaching the intervertebral foramina, join 
directly the ventral caudal plexus rather than 
the caudal nerves The transverse branches 
extend between the internal aspects of the 
first three caudal ganglia (Bosa, 1965) 


BIBLIOGRAPHY 


Bom V M and R Cetty I960 Somatic and autonomic nerve* of the 
lumbar macral and coccygeal region* of the dotneioc pig (Sul 
icrofa domntlcaj. loma Stale J Set 44 45-77 
Bo,4 f, J , 1932 - D |« Anatom e de* lumbo*acraIen und coecygealen 
Abschn in de* Trvneus tympathicu* be) Hautsiugetiercn. 
Znchr Anal Enwickl Ceseh. S7 je2-424 
Bourdelle E. and C Bressou. 1964 In Anatomie Rigxn-ilr de* 
Animau* Domeanque* By L. Montand E. Bourdelle and C 
Bressou Fascicule III Pari. J B BaiJhdrr et FU» Editeur, 
Ghoshal N C and R. Cetty 1969 Postdlaphragmatic deposition of 
Die pars sympathies and major autonomic ganglia of ih e do- 
mesne pi* (Sat icrofa domcittco). Anat Ana. 125 400-411 
Uctnda. S 1929 Morphologic he Studien Dber da, sympathetiKhe 
Nervcn system de* Schmeine* (S«. ruulicirt). IL Mltteflung. 
Eros! und BauchteiL Kyoto Japan. Anat Inn Imperial 
von Schumacher S 1905. Ober die Nerven des Sc liman*,, £ct 
Siugetiere und de* Menschen m t besondeict Berilekilchugung 
de* sympathise hen Ciena* rranget. Vienna. Sltaungtberiehte der 
Kaisere. A Lad emir der WUsensehaften. Mathematitcb-Natnr- 
wissentcha ftiic he Klasse XIV (II It 569-604 



CHAPTER 


PORCINE SENSE 
ORGANS AND 
COMMON 
INTEGUMENT 


THE ORGAN OF VISION 

by C D. Diesem 


THE ORBIT 

The skull of the pig, like that of the dog, 
shows more variation than is seen in other 
species of domestic animals The difference 
in porcine skull shape is due to the variation 
of the facial bones in vanous breeds of swine 
The shape of bones of the cranium is much 
less modified and, as a result, the orbit of 
the vanous porcine breeds is similar in size 
and shape The pig may have an angle of 80 
to 120 degrees between its orbital axes The 
visual axes of the hog do not coincide with 
the orbital axes, consequently the angle 
found between the former will approximate 
60 to 70 degrees 

The e>es of the hog do not protrude from 
the orbit, so the pig does not have a field of 
vision as extensive as that of the cow, never- 
theless, the porcine field of vision is probably 
260 to 275 degrees Swine may have a binoc- 
ular field of vision ahead of them that ma> 
cover 30 to 50. degrees (Pnnce et al , 1960) 

The frontal bone forms the roof of the orbit 
and an extcnslv e portion of the medial wall 
Tlit* supraorbital foramen is found in the dor- 
sal portion of the frontal bone just below the 
orbital margin, its diameter vanes from 3 to 
5 tnni The ethmoidal foramen is only a short 
distance from the junction of the frontal 
bone and the sphenoid bones on the medial 
orbital wall, its diameter is 1 5 to 2 0 mm 
The trochlear fovea is a depression found 
ai>out 1 im caudal to the orbital margin and 
about tht s imo distance v cntral and rostral to 


the supraorbital foramen This fossa lodges 
the trochlea for the obhquus dorsalis muscle 
The supraorbital process doe s not project the 
complete distance to the zygomatic arch and, 
as a result, there is not a complete circle of 
bone enclosing the orbit An orbital ligament 
of connective tissue does extend between the 
zygomatic process of the frontal bone and the 
zygomatic arch 

The lacrimal bone in the hog has an orbital 
and a facial surface The portion of the bone 
that marks the margin of the orbit is per- 
forated by two foramina, the lacnmal fora- 
mina In some skulls there may be one, two 
or three lacnmal foramina nnd they may be 
found rostral or caudal to the orbital margin 
These foramina vary m size but they may be 
3 to 4 mm in width and 4 to 5 mm in length 
The lacrimal bone also has n deep fossa that 
may be 1 cm in length and 0 5 cm in width 
in some skulls, yet in other porcine skulls it 
may be just a slight depression This depres- 
sion accommodates the deep (Hardenan) 
gland of the third eyelid and the bulb 

The zygomatic bone forms the rostral 
boundary of the orbit with the maxillary and 
lacrimal bones The temporal process of the 
z> gomatic bone extendscaudally v cntral to the 
temporal bone to help to form a large portion 
of the z> gomatic arch and the lateral margin 
or the orbit The temporal process of this 
bone is much larger, comparatively speaking, 
in the pig than in «omc of tfi c other domestic 
animals 

The maxilla forms a portion of the rostral 

1409 



1410 


PORCINE 


and rostroventral part of the orbit The maxil 
lary foramen leads away from the ventral 
portion of the orbit and is quite large the 
horizontal diameter may be 15 to 18 mm and 
the \ ertical diameter 8 to 10 mm The maxilla 
overlaps a large portion of the vertical part 
of the palatine bone as it projects ventrad 
from the orbit and lies between the ramus of 
the mandible and the caudal choanae 
The wing of the presphenoid bone is cov 
ered by the frontal bone rostrally but forms 
a large portion of the medial and caudal parts 
of the orbit The wing of the basisphenoid 
bone projects ventrally and fuses with the 
palatine and pterygoid bones but plays a small 
part in the formation of the orbit 
The ethmoid bone may form a small portion 
of the medial wall in some porcine orbits If 
some of the bone is exposed it will be found 
ventral to the lacnmal and frontal bone caudal 
to the maxilla and rostral to the sphenoid bone 
The ethmoid bone does not appear in the orbit 
of many porcine skulls because it is overlain 
by the other bones of the orbit such as the 
frontal bone and the maxilla. It was not found 
to be exposed in the breeds of swine which 
have brachy cephalic skulls 


The vertical diameter of the bony orbital 
margin is approximately 4 5 cm and the 
horizontal diameter of the bony orbit is 
approximately 3 5 cm These dimensions 
showed little variation in raesaticephalic 
and brachycephalic skulls The depth of the 
orbit is approximately 5 2 cm The space be 
tween the orbits is approximately 6 to 7 cm. 


ACCESSORY OCULAR ORGANS 
The Eyelids and Conjunctiva 

The eyelids of the pig are not so thin as 
they are in the horse In fact the lids are rela 
lively thick and their movement is limited. 
There is considerable fat tissue under the skin 
and the conjunctiva (Fig 47-1) The upper 
lids contain heavy cilia, but in die lower lids 
cilia are absent (Fig 47-1) The upper lid 
may exhibit a transverse fold and underly 
ing the skin of this lid one finds a thick con 
nective tissue layer that extends to the orbital 
margin This connective tissue resembles the 
tarsal plate In some animals but it apparently 


Uer>m« « (srcncn) 



FIGURE 47-1 The supraorbital portion of the frontal bone and the dor*»l orbital wall bare been removed 
to expose the brain and orbital content*. Arteries and tcIbb adjacent to the orbit are exposed. 



47- PORCINE SENSE ORGANS AND COMMON INTEGUMENT 


1411 



FIGURE 47-2. Medial orbital structures exposed by rotating the bulb approximately 90° laterally from its 
normal position in the orbit. 


Venous sinus, gland of the third eyelid, Harder’s gland and trochlear cartilage are exposed 


is not too important in maintaining the 
rigidity of the upper lid The tarsal glands 
(Meibomian) are not so well developed in the 
pig as they are in the other animals. The 
glands in the lower lid are smaller than they 
are in the upper lid. The pig has a great num- 
ber of sweat glands in the lids and some 
sebaceous glands that are associated with the 
hairs. 

In addition to the connective tissue found 
in the lid of the pig, some of the superficial 
muscles are well developed. The orbicularis 
oculi muscle is quite prominent. 

The third cjeiid in the pig is anchor- or 
T-shaped, with the broadest portion of the 
cartilage being nearest the free edge of the 
lid The cartilage is covered by membrane 
(nictitating membrane), and the tissue which 
covers it contains many lymph nodules. The 
shaft of the cartilage is intimately associ- 
ated with the superficial (nictitans) gland. 
Tills gland lies on the palpebral side of the 
cartilage; histologically ft is a mixed gland 
approximately 4 mm thick and 1.5 cm in 
width in the li\ing anim.il the gland has a 
brownish or reddish yellow color. The three 
to five ducts open with the ducts of the deep 
gland (llardertan gland) on the bulbar sur- 
face of the cartilage of the third eyelid A 
Compact layer of connective tissue is found 
between the superficial and deep glands The 


pig is one of few animals to possess both a 
deep (Harderian) and a superficial (nictitans) 
gland. The deep gland is quite large in the pig 
and occupies the area between the cartilage 
of the third eyelid and the eyeball; it also 
occupies some of the area between the bulb 
and the medial orbital wall (Fig. 47-2). In 
an adult hog the gland may have a longitudi- 
nal diameter of 2 to 3 cm and a transverse 
diameter of 1.0 to 1.5 cm; it is 0.5 to 1.0 cm 
thick. The bulk of the gland lies to the medial 
side of the orbit and in a fossa of the lacrimal 
bone. Apparently the growth of the gland 
produces the fossa as the lacrimal bone 
ossifies around the soft tissues of the orbit. 
The gland is surrounded by a venous sinus 
that is formed by the outer wall of the peri- 
orbita, while the inner wall blends with the 
fascia that covers the recti medialis and ven- 
tralis muscles. The gland has connective 
tissue fibers that attach it to the walls of ad- 
jacent structures. The ducts of the gland 
arise on a shallow ledge of the bulbar surface. 
It opens on the bulbar surface of the cartilage 
of the third eyelid. 


The lacrimal Apparatus 

The lacrimal gland of the pig Is not so large 
as it is In some of the other domestic animal 



1413 


47-rORCINE SENSE ORGANS AND COMMON INTEGUMENT 


Men ngeal morg n 




•n , , , . , portion of thr retractor mu*cl*««nd the superficial layer* of fascia 

Tt* Uvator palp^hrae superiorfi dorsal «etu* dorsal ponion 

* 'Vf betll nr noved. 



PORCINE 


1414 

mately 22 mm at the equator of the bulb 
These figures were taken from measurements 
made on hogs weighing approximately 225 
pounds that were five to six months of age 
The dimensions given b> Pnncc tt al (1900) 
were 22 to 24 mm for the anterior posterior 
dimension the horizontal diameter was 2G 
to 27 mm and the vertical diameter was 25 
mm This difference in Pnncc s figures can 
be explained by the fact that he used eyes 
from larger and more mature hogs 


FIBROUS TUNIC 

Scleiia The sclera may be highly pig 
mented in pigs with dark hair coats. In pigs 
with white hair coats the pigmentation of the 
sclera may be reduced The pigmentation of 
the sclera may be pronounced near the limbus 
of the bulb in the cribriform area and along 
the course of the long posterior ciliary vessels 
Pigmentation may continue from the cribn 
form area onto the connective tissue that 
covers the optic nerve 
The thickness of the sclera may vary at 
different locations It measures approximately 

0 55 mm at the limbus and 0 5 to 0 8 mm at 
the equator, at the area cnbrosa it may be 

1 0 to 1 2 mm (Martin, 1915) The sclera is 
not the same thickness in all quadrants of the 
bulb, according to observations reported by 
Martin (1915), the sclera is thicker on the 
medial wall of the bulb than on the lateral 
wall 

Cornea The cornea is oval, with the 
greater dimension being horizontal, a length 
of 14 to 16 mm, and the vertical dimension 
13 to 14 mm The thickness of the cornea is 
less than 1 mm in the specimens examined 
There are five layers to the cornea as in the 
other domestic animals The layers and thick' 
nesses of these layers from anterior to posteri 
orare (1) surface epithelium whichconsistsof 
several layers of cells, the most anterior being 
composed of squamous cells and the more 
postenor being columnar or polyhedral, this 
layer is approximately 50 to 55 n thick, (2) 
anterior limiting layer (Bowman’s mem 
brane) is not easy to distinguish m the pig, 

(3) substantia propria is 0 7 mm thick 

(4) postenor limiting layer (Descemet’s mem 
brane) is from 8 to 12n, and (5) endothelial 
layer of the cornea is about 5p thick Martin 
(1915) states that the middle portion of the 
cornea may be 1 0 to 1 2 mm thick and the 
penpherv may be 0 5 to 0 8 mm thick 

The junction of the cornea and sclera at 
the limbus is not distinct The iridocorneal 
angle that is found between the cornea and 
the peripheral ins is adjacent to a v enous plex 
us, which is undoubtedly the drainage struc 
ture for the antenor chamber There is no 


single canal ofSchlemm, but there are several 

veins (scleral venous sinus) and they appear 
to be free of blood in sectioned specimens 
The comcil innervation is from fibers that 
leave the ciliary nerves and pass anteriorly be 
tween the choroid or sclera to the vicinity of 
the ciliary body The fibers to the cornea 
leave those to the ciliary body and iris and 
pass anteriorly to the cornea (Prince ct al , 
I960) 


VASCULAR TUNIC 

Choroid The outstanding difference be- 
tween the choroid of the pig and that of the 
other domestic animals is the fact that the 
pig has no tapetum Looking Into the eye of 
the hog one secs an orange red color very 
similar to that seen in the fundus of man 
Histologically the porcine choroid will be 
found to vary in thickness, the membrane 
between the choroid and the retina, basal 
(Bruch's) membrane, is thicker in the pig 
and can be readily defined 
Cii iaiii noDV. This structure is very much 
like the ciliary body of other domestic animals 
in that it has some radial fibers and long! 
tudinal muscle fibers but no circular fibers 
The number of Large ciliary processes exceeds 
90. and these alternate with smaller pro- 
cesses These processes are attached to the 
lens by zonular fibers The ciliary body is 
better developed on the medial and ventral 
aspects of the eye than it is on the lateral and 
dorsal portions of the eye 
Inis The pupil of the porcine eye is slightly 
oval when in normal position, with the great- 
est dimension being horizontal The pupil 
is round when it is dilated The concentric 
fibers in the ins extend to the pupillary border, 
and the stroma of the iris is profusely pig- 
mented The dilator fibers are present but 
more difficult to see than the constrictor 
fibers The periphery of the ins is closely 
attached to the cornea. 

The blood vascular system to the ins forms 
a major arcade at the penphery of the iris 
and then forms an extensive network of ves 
sels throughout the stroma to the pupillary 
margin There are no granula irtdica (<£ 
corpora nigra) found around the penphery 
of the pupil in the pig 


NERVOUS TUNIC 

Retina The pig has a diurnal type of ac 
tivity and its habits are such that it uses its 
eyes under conditions that require the pres 
ence of rods and cones in the retina. The 
retinal blood vessels are found in the fibrous 
layer of the retina although some of them do 



7— PORCINE SENSE ORGANS AND COMMON INTEGUMENT 


project toward the vitreous. There axe vtans 
and arteries projecting from the optic disc 
area. There are usually four arteries ana a 
number of veins present. There may be an 
area resembling a macular area Present in 
the pig. The presence of a macula is sug 
gested by an area of the retina that is free of 

blood vessels. , . 

It has been previously stated that the pig 
fundus is lacking a tapetum. The fundus has 
a yellow-red color when viewed with an 
ophthalmoscope. The veins appear to have a 
larger diameter than the arteries and they 
do not show the arborization that characterizes 
the arteries. The optic disc is oval in outhn , 

with the transverse diameter being the larger. 

The nerve fibers extending from the disc are 
medullated and they may appear to be in 
bundles. The non-vascular area of 
fundus is lateral to the optic disc. This avas- 
cularity of a specific area resembles the 
macula of the fundus of primates. Whether 
the pig utilizes this area for specific visual 
tasks is not known. , , 

The lamina cribrosa is well developed in 
the pig and this connective tissue continues 
posterior for a short distance to send s p 
between the bundles of the optic nerve. The 
lamina cribrosa may contain pigmenteu 
cells and, as a result, the area cribrosa may 
appear dark, and pigmented connective tissue 


1415 


septa may cause the optic nerve to take on a 
dark appearance. 

CHAMBERS OF THE EYE 

The anterior chamber of the eye is enclosed 
anteriorly by the comea and posteriorly by the 
iris and lens. It communicates through the 
pupil with the posterior chamber of the eye, 
this is a small anular space, triangular in 
cross-section, which is bounded anteriorly by 
the ins, posteriorly by the peripheral part of 
the lens and its ligaments, and externally by 
the ciliary processes. The antenor and posteri- 
or chambers are filled by the aqueous humor 
a clear fluid. The vitreous chamber is situated 
between the crystalline lens and the retina, 
and contains the vitreous body. 

refractive media 

The comea, lens, aqueous humor and vitre- 
ous body all serve as refractive media and are 
described in detail In the General Secdon. 

Vessels and nehves. (Figs. 47-5 to 9). 
The skull of the pig does not have an alar 
canal thus, the maxillary artery comes into 
the ventral orbital area without passing 
through a bony canal. The artery travels 


Locrlmol o Fro nloi rv 


Superior palpebral < 


Loenmol n. iOorvil branch) 



fc^-lre crane) 


rKlvt m . 

nr.fttt ,7-C. PeriotMU eotoplelelr removed recto, mo.ele., .nd .operteW W 



1416 


PORCINE 


Suo oorb to 



FIGURE 47-7 Posterior view or the bulb showing the relation of the ciliary arteries and nerves to the optic 

m.r>e 

The caudal portion of the retractor muscle has been removed 

ventral to the pterygoid crest and rostra] to the domestic animals This artery upon entering 
crest gives origin to the external ophthalmic the orbit gives off a lacnmal artery (Fig 
artery which passes through the periorbita 47-6) the lacnmal artery is continued be 

and between the recti dorsalis and lateralis yond the lacnmal gland by branches to the 

muscles The external ophthalmic artery has eyelids and the conjunctivae 
the longest extraorbital course of any of the The venous system of the porcine orbit does 



F I CURL 47-8 Dorsolateral view of the caudal portion of the orbit 


Tlie sphenoid bones have been removed 10 expose the trigem nal nerve Note the manner in which zygomatic and 
lacrimal nerve brand es leave the tngem nal nerve trunk. 



47— PORCINE SENSE ORGANS AND COMMON INTEGUMENT 


1417 


Dorsal rectus m fcut 



Ventro oB que m Gnse Uoo) 
^ Ocu omo or a Ventro bronchi 

Harder 


, rr bXhowuig U» ™-.r urtenes to the rectus musc.es 

FIGURE 47-9 Ventrolateral view ot the bulb show ing 

■ This is contrary to the observations made 
flhl dog hors 3 cow by Ruskell (Pnnce 
et al, I960) It fh“_uld be stated that these 


not resemble that of some of the otl,t ' r d °I"“ 
tic animals because of the extensive jMaUon 
of the vascular system between thc p -norln 
and the rectus muscles This sheath is essen 
Hally a large envelope that covers mostolthe 
intraorbital contents posterior to the. ! 

of the bulb Where the envelope, docs not 

completely cover tissues, such as t 
muscles of the eyeball, there a*™**" 
cross connections that enable all po 
the sheath to communicate 

The motor innervation to the eye of the hog 
passes from the cranium to the or 
via the foramen orbitorotundum 
sory innervation to the retina passe 
optic nerve The optic nerve after leaving the 
optic cluasma, enters the orbit 
optic foramen It turns medial. thcn dowo 
lateral and then ventral before h enters the 
bulb medial to the posterior pole The ophtnai 
mic nerve emerges from the dorsal P . 
of the foramen orbitorotundum, , 

nerve arises from the ophthalmic ne iy . 
fore it emerges from the foramen 
(Prince et al , 1960) noted the 
supraorbital branch of the frontal n 
the pig because of the failure of any 
fibers to attain the supraorbital area in the 
porcine head (Tig. 47-6) The long P 
ciliary, nasociliary, infrairochlear, p 
mic lacrimal and zygomaticotemporal 
art described in detail in Chapter 46 
The maxillary nerve (Fig 47-5) l ^ °n he 
ventral portion or the foramen orbitoroUm 
dum, and arising from tills nerve white 1 
still in die cranial vault one can scc tnc 
fibers or the zygomaticofacial branch sep 
and pass to the area or the lower 11 
zygomaticotemporal branch may a [* se 
the ophUialmic nerve rather tlian the maxil 


Pt al 19bU) it snuuiu ut 

zygomatic branches arise more proximal in 

, 1 than they do in the other domestic 
snecies The ongin of the zygomatic is very 
close to the trigeminal ganglion of the tn 
eemtnal nerve Individual vanauon in the 
dfstnbution of fibers of the zygomatic nerve 
was noted This variation was quite apparent 
when one tried to determine whether fibers 
came from the ophthalmic or maxillary nerve 
The maxillary nerve, after giving ongin o 
the zygomatic branches, courses ventral to 
the eve It supplies fibers to the pterygopala 
fne (sphenopalatine). Infraorbital and pala 
tine nerves and thus terminates in the rostral 
pterygopalatine fossa. The trochlear oculo 
motor and abducent nerves (Fig 47-9) are 
desenbed in detail in Chapter 46 

bibliography 

AdlM F 11 19C3 Physiology of the Eye Clinical Application. Sl 

BloonTw" "end IX 'V Fawcett 19C8. A Textbook of HUtolomf 0th e«t 
Philadelphia W B Saunders Company 
Bonavotonta, A 19M Proprioceptor nerve, of the extrtn.lc muscles 
of the eye In pic*- Atti Soc lul Set Vet 12 52*2 S24 
Darcel C. le Q L Milo. K- J Aiery and A. H- IJalnbortHiK^ 1900- 
MkrophtKilmU and microphthalmia In plxlets. J Path. Bact 

Mari to ^p' HH5 Lrhrbuch der Anatomie dtr »UtJ«tiere Band II 
lUlfter 2. Stuittart 'erU» von Schkkhardt und Ebwr 
Montane U E- Bourdelle W Anatomle W i ticnale 

dn Anlmaux Uomevtlque*. Pari*. J B BallllJnt 
Prince H C. D Dtevero I ExUtlv and C. L. Ruskell. 1PW1 Anatomy 
and MlitolotY of the Frr and Otbtt in IWnrvtk A til mats Sprint 
HI ChaHra C Thomas. 

Wallt C. U 1043 TV Vmdiniie 1 ye Rlownteld Hills MkMxait, 
Cnr.beook Institute of Science 
Zirtoehtnann. O F- Acktweh. and It Cnu J941 

and Haum a Itandbuch det veriVklwnden Anatoenl* A~r Ka»v 
twre lBth ed Betfin. sprinter 



1418 


PORCINE 


EAR (ORGANUM VESTIBULOCOCHLEARE [AURIS]) 

by S. S. 


EXTERNAl EAR 


The external car differs considerably in size, 
thickness and position in the various breeds 
It may be earned vertically, inclined inward, 
or hang ventxally It is relatively wide and is 
little curved except at the base It consists of 
the auricle (pinna) and the external acoustic 
meatus It is constituted of three cartilages — 
auncular, scutiform and d«anular The first 
two cartilages are covered by the superficial 
muscles and the skin, while the anular carti- 
lage lies deep to the base of the auricular car- 
tilage The anular and auricular cartilages 
form the boundaries of the ear canal or exter- 
nal acoustic meatus 

The auricular cartilage is the main cartilage 
of the external car and is responsible for form 
ing the basis of the visible portion of the ear It 
is somewhat funnel shaped, although its ma 
jor portion appears like a leaf Its medial part 
at its base is rolled like an incomplete tube, 
while its apex is pointed and is directed dorsal 
ly It has two surfaces and two borders The 
convex or outer surface faces medially, the 
concave or inner surface faces laterally, with 
the apex directed dorsally, while at the base it 
is attached to the osseous external acoustic 
meatus of the temporal bone Therefore, the 
borders are rostral and caudal with regard to 
the body plane The whole cartilage through 
out is pierced by a number of small foramina 
which permit the passage of blood vessels 
from the external to the internal surface 
The helix, the free margin of the cartilage, 
is slightly folded while the «f>anthclix is present 
in the form of a low transverse ridge on the 
medial wall of the proximal part of the car 
canal The triangular area lying between the 
helix and antihelix is the scapha The tragus, 
which is an irregular rectangular plate of car 
tilage, curves caudomedially, at the outer sur 
face it is strongly convex. It is continuous w ith 
the antitragus, with which it completes the 
caudal boundary of the opening into the ear 
canal On the inner surface it forms a shallow 
groove It is separated from the antitragus by 
a small notch, the inlertragic incisure This is 
the cartilaginous convexity which forms the 
caudal prominence at the base of the ear The 
antitragus Is a cartilaginous plate which lies 
caudal to the tragus In the pig it has three por 
tions— medial and lateral processes and a fold 
The medial process is a rectangular plate 
which curves caudomedially and is separated 
from the tragus by the intertragic incisure 
and from the fold by the pretragic incisure 


Gandhi 


The fold is a rectangular plate, separated from 
the medial and lateral processes by the pre- 
tragic incisures The lateral process is com- 
paratively smaller; its free apex ends in a sharp 
process, the styloid process 
The rostral border ( margo tragicus ) of the 
auncular cartilage is irregularly straight Al- 
most in the middle of this border is a deep 
notch forming the spine of the helix. The 
caudal border ( margo antltraglcus ) Is ser- 
rated, having a number of small cartilaginous 
projections. At the base or caudal end of the 
caudal process it is separated from the tragus 
and antitragus by a deep wide notch, the anti- 
tragohellcine. The inner, or lateral, surface Is 
correspondingly concave from side to side At 
the base is a deep concavity or groove, the 
concha! cavity, formed by the concave inner 
surface of the tragus It is bounded by the ant- 
helix, tragus and antitragus The conchal 
cavity is continuous with the external acoustic 
meatus The antitragus is responsible for the 
formation of two thirds of the bony canal (the 
other third of which is formed by the anular 
cartilage) 

The skin covering the cartilage is more 
closely attached to the Inner surface of the 
auricular cartilage than to its outer surface. It 
is pigmented, and its color varies depending 
upon the breed It is thickened and more close- 
ly attached to the free apex of the auricular 
cartilage than to Its base There is less hair on 
the inner surface than on the outer surface, 
and it decreases from the base to the apex. On 
the inner surface there are two to three cuta- 
neous ridges which are very prominent at the 
base and diminish towards the apex so that in 
the proximal one third of the inner surface 
(towards the apex) there arc no ridges 

The scutiform cartilage is a comparatively 
small bootlike cartilaginous plate which is 
located at the rostromedial aspect of the base 
of the ear and is almost completely covered 
superficially by the rostral and medial groups 
of muscles 

The 4>anular cartilage is an irregular rec 
tangular plate It is attached to the osseous ex- 
ternal acoustic meatus ventrally and to the 
lower part of the auricular cartilage dorsally 
It is convex externally and correspondingly 
concave internally Along with the auncular 
cartilage, it is responsible for the formation of 
the boundary of the ear canal. It forms ap- 
proximately one third of the media! aspect of 
the ear canal It is almost double in its width 
at its attachment with the auncular cartilage 
and at its termination with the osseous exter- 
nal acoustic meatus, it is reduced 



47— PORCINE SENSE ORGANS AND COMMON INTEGUMENT 


1419 


For a description of the auricular muscles 
see chapter 39 


MIDDLE EAR (AUR1S MEDIA 
[CAVUM TYMPANI]) 


The middle ear of the pig is different than 
that of the other domestic animals due to the 
different conformation of the bones of the 
skull In the pig the auditory tube is much 
longer than in other animals It is directed 
ventromedially and, therefore, the tympanic 
cavity is located more ventraily and deeper 
than in other domestic animals The middle 
ear is composed of the tympanic cavity and the 
auditory tube The tympanic cavity houses the 
auditory ossicles, muscles and the chorda 
tympani nerve The tympanic cavity as a whole 
is much smaller in the pig as compared toother 
domestic animals As in the other domestic 
animals, it can be divided into three parts— 
dorsal, or epitympamc recess, middle, or tym 
panic cavity proper, and ventral, or bulla tym 
paiuca, which is very laige and well developed 
in the pig 

The epitympamc recess is very small and 
lies rostal to the pars tensa of the tympanic 
membrane in the form of a small concave de 
pression on the medial aspect It houses the 
head and neck of the malleus and part of the 
body of the incus 

The tympanic oavjty proper is much smaller 
compared to the other domestic animals and 
s hes mainly ventral to the circular pars tensa 
of the tympanic membrane There is no cavity 
surrounding the medial aspect of the pars 
tensa, but the cavity around the lateral aspect 
is strongly concave The cavity lying ventral 
to the membrane is strongly concave, small 
&nd porous in structure, and is continuous 
the tympanic bulla Opposite to the 
wmpanic membrane, on the medial aspect, is 
o very well developed, strongly convex and 
funded bony eminence, the promontonum 
t ne promontorium in the pig is much better 
developed compared to other animals, but the 
oppression facing dorsnlly, the cochlear win- 
dow which houses the cochlea, is much 
smaller It is more or less elliptical in outline 
ond is covered by a thin membranous sheet, 
me second or) tympanic membrane It is 

•ru * ossociated with the stapes and incus 

Hie tympanic bulla is very well developed 
na large It is the lowermost part of the 
tympanic cavity when viewed dorsally 
“trough the auditory tube and is strongly con 
in the inner surface It is incommunica 
uon vviih the tympanic cavity proper by nu- 
merous pomus cells 

*ne tympanic membrane is quite different 


than that of the bovine and goat, although it is 
somewhat similar to that of the sheep In the 
pig it is a very thin membranous lining ex- 
tending from the tympanic incisure to the 
dorsal aspect of the tympanic cavity proper 
As in other animals it can be divided into two 
parts— pars tensa and pars flaccida The pars 
flaccida is quite well developed in the pig as 
compared to otheranimals Itis approximately 
triangular in outline in its dorsal portion, but 
as it descends towards the epitympamc recess 
it becomes a rectangular thm, flat mem- 
branous sheet which terminates at the lateral 
process of the malleus The irregularly cir 
cular membranous sheet lying caudal to the 
lateral process is the pars tensa It is smaller 
m the pig as compared to other domestic 
animals It forms the medial, dorsal and 
lateral boundaries of the tympanic cavity 
proper The peripheral lining of this part is 
much less developed than in the bovine, goat 
and sheep, in that order The whole tympanic 
membrane is very light pink in color with the 
color of the peripheral lining of the pars tensa 
being almost the same, contrary to that of the 
bovine and goat The whole medial surface is 
not convex, it appears to be irregularly con- 
cavoconvex Almost m its middle the manu- 
brium is very loosely attached Traction on the 
medial surface of the pars tensa of the pig is 
much less than irrother animals The lateral 
surface of the pars tensa is also irregularly 
concavoconvex The stna mallearis is almost 
indistinct The concavity opposite the ter- 
mination of the manubrium, on the lateral 
surface, is not well marked, and therefore, 
the umbo rriembranae tympani is not very 
distinct 

The auditory ossicles of the pig are very 
small as compared to other domestic animals 
The malleus is small and slender, the incus is 
triangular in shape, with two crura extending 
from either side of the base of the tnangle, 
and the stapes is the smallest Only the manu- 
brium of the malleus is laterally placed, other- 
wise all these bones are medial in position 

The malleus js much less developed as com 
pared to other animals, but it presents essenti 
ally the same features for description It can 
be described ns having a head, neck and 
manubrium The head Is very poori> de- 
veloped and is slender in outline It is slightly 
curved laterally, although it lies m a medial 
plane and articulates with the bodj of the 
incus The neck is also very slender, distinct 
and well developed At the junction of the 
neck and manubrium from its lateral aspect, a 
prominent, well developed lateral process ex 
tends laterally and is embedded in the tym 
panic membrane, dividing it into the pars 
flaccida and pars tensa The lateral process Is 
v cry prominar unpared with that of the 
other domett ah At the same level 



1420 PORCINE 


from its medial aspect arises the well de- 
veloped muscular process extending medially 
for the attachment of the tensor lympanl 
muscle The muscular process lacks a hook 
and, therefore, the tensor tympani is not very 
firmly attached Lying caudal to the muscular 
process is the small rostral (long) process ex- 
tending rostrally It is the least developed 
process in the pig The neck continues cau 
dally as the manubrium (handle) which is al 
most double the width of the neck, but tapers 
caudolaterally and at its point of termination 
is like the point of a pin The manubrium is 
the most well developed part of the malleus 
It is triangular in outline, having three sur 
faces It is loosely attached to the medial sur 
face of the pars tensa of the tympanic mem 
brane, except at its termination where the 
attachment is very firm It lies almost in the 
center of the circular pars tensa 
The incus lies caudally and medially to the 
malleus It is not very well developed as com 
pared to other domestic animals It can be de- 
scribed as having a triangular body and two 
crura The triangular body lies in the medial 
plane, with its apex dorsolaterally and its base 
vcntromediaUy On its flat medial surface it 
has a small groove The caudal aspect is in 
articulation with the slender head of the mal 
leus and lies in the epitympanic recess A 
small projection arises from the apex of the 
body The two crura are given off from the 
angles of the base of the triangle, one extend- 
ing rostrad (long cni») and the other caudad 
(short crus) in a medial direction Both 
diverge from the same point At the termina 


lion of the long crus is a small flattened pro- 
jection, the lenticular process, which articu- 
lates with the head of the stapes 

Although the stapes is the smallest bone.it 
is well developed in the pig as compared to the 
other domestic animals It has a uniform 
diameter throughout, although it is slightly 
rounded and narrower at its head It lias a 
head, neck, two crura and a base The head Is 
small and convex and is adapted for articula- 
tion with the lenticular process of the incus 
The neck is indistinct and broad and splits 
into two crura which are separated from each 
other by a deep, well-developed depression 
Both rostral and cauda! crura arc the same 
length, they are joined to each other and to 
the base of the stapes by a connective mem 
brane The base is broader than the head. The 
stapes lies partly in a fossa situated along the 
medial aspect of the vestibular window, al- 
most in a horizontal plane, with the head in- 
clined caudally and the base facing rostrally. 

There arc two muscles associated with the 
auditory ossicles The tensor tympani muscle 
is not very well developed and is attached to 
the muscular process of the malleous The 
stapedius muscle is whitish in color and is 
better developed It is associated with the 
stapes 

The auditory (Eustachian) tube is short; its 
pharyngeal opening is situated in the upper 
part of the wall of the pharynx, immediately 
caudal to the choanac It is somewhat in- 
fundibular, and is bounded medially by a 
thick fold of mucous membrane (torn* 
tubarius ) 


COMMON INTEGUMENT 

by C. R. Ellenport 


According to Montagna and Lobitz (1964) 
the skin of the pig has a remarkable number 
of focal specializations, some of these being 
associated with rich glandular fields The 
most significant has occurred in the rhinar 
lum, or snout Caudal to the angle of diver 
gence of the mandibles is a round, raised, 
nevus bke structure, the mental glands, com 
posed of sebaceous and apocrine glands, and 
very coarse vibnssae 

The surface of the skin of the pig is creased 
by delicate intersecting sulci, which when 
shaved attain a superficial resemblance to the 
skin of man The skin is thickest, and with a 
correspondingly more elaborate understruc 
ture, on the glabrous surface of the bps, on 
the snout and between the toes (Montagna 


and Lobitz, 1964) The thickness of the skin 
in improved breeds is 1 to 2 mm, except in the 
adult boar, in which the conum of the shoul 
der may become 3 5 to 4 mm Fat usually 
accumulates in the subcutis and forms a dis- 
tinct and often extremely thick panniculus 
adiposus over the greater part of the body 
(Sisson, 1921) 

Montagna and Lobitz (1964) state that 
though breeds vary in the profusion of their 
hairs, pigs have a moderate to sparse coat of 
hair, longer and coarser on the dorsum than 
on the belly The hairs are shorter and more 
crowded togethenn areas where the expansion 
of the skin surface is minimal, such as be- 
tween the toes, at the base of the ears, on the 
head, and in the axillary and inguinal regions 



1421 


47— PORCINE SENSE ORGANS AND COMMON INTEGUMENT 




FIGURE 47-10 Superficial features of eaternal 
nose of 6 month old swine 


Top Lateral view A apex B planum rostrale Bottom 
Rostral view A Apex B planum rostrale C nares D 
philtrum a glabrous area on snout disc b pilary area on 
snout due. (By Hillmann) 


Short, coarse vibnssae are widespread over 
the snout, the muzzle, and on the upper and 
lower lips, they are much longer on the men 
hil glands The sparse pelage is composed of 
thick bnstles between which is a relatively 
small population of thin hairs almost as long 
as the bnstles These, however, do not form a 
true underhair coat Even fairly hirsute am 
trials have a somewhat exposed skin There 
Rre no true glabrous surfaces other than the 
tabial borders The hairs may grow in groups 
oi two or three, but are usually found singly 
According to Montagna and Lobitz (1964), 
nf ♦u l0st si snificant specialization of the skin 
n P*5 is found in the snout, which is a 
fattened, expanded structure modified for the 
p of rooting. The snout has the only sur- 


face that is comparable to the friction areas of 
nonhoofed mammals (palms and soles), it is 
different, however, in having over its surface 
widely spaced, short vibnssae The snout has 
undergone admirable adaptation it has a very 
thick epidermis, under which are many tac- 
tile nerve endings, end organs and sinus hair 
follicles Like the friction surface of other 
mammals the surface of the snout is kept 
moist by the secretion of the special serous 
glands deep in the dermis There are no 
apocrine sweat glands in the snout 
According to Hillmann,- the rostral surface 
of the snout (planum rostrale) is covered 
with short sinus hairs (pilary area) except for 
the dorsal portion transcribing a crescent 
shaped area (apex nast) (Fig 47-10 bottom) 
from 10 to 2 o’clock This hairless (glabrous) 
area is continued caudally on the dorsum of 
the snout in a triangular shape (Fig 47-10 
top) It presents a greatly thickened stratum 
comeum, with small glandular ducts opening 
onto its surface The area immediately sur- 
rounding the nares is devoid of hair follicles 
with the exception of the dorsolateral quad 
rant (a raised, slight irregularity in the wall of 
the nares, presenting short vibnssae) 

Hillmann” feels the difference m the na 
turn of the vasculature of the two areas, pilary 
vs glabrous, is of interest In the pilaxyarea 
one can observe a concentric relationslup (3 
to 5 nngs) of the vascular dermal papillae, 
with the most internal sheath surrounding 
the hair follicle itself (Fig 47-11 bottom) In 
contrast, the glabrous apex of the snout pre 
sents numerous, sharp, conical, vascular 
dermal papillae (Fig 50-11 top) 

According to Sisson (1921) the sebaceous 
glands are, in genera], smaUand much fel '' er 
than in the other animals The sweat glands, 
on the other hand, are large, yellow or brown 
ish in color, and are m many places visible to 
the naked eye At the medial palmar side of 
the carpus there are small cutaneous diver 
ticula, the carpal glands, into which nu 
merous compound coil glands open Large 
glands also occur in the skin of the digits and 
interdigital spaces Compound tubular glands 
Lie present in the skin of the snout Large 
sebaceous and sweat glands are found at the 
entrance to the preputial diverticulum 

■Se hoofs or claws and their conum re 
semble those of the ox, but the [bulbs^ « 

STounSTurface h™ ^"SSbeS? defined 
^"“vhS small The hoofs of the 
accessory digits are more developed and their 
parts better differentiated than those of the 
ox (Sisson, 1921) 


i personal communication 1973 


1422 


PORCINF 



HGUItb 47-11 Photographs of cor 
rosfon ttpecimena of the Injected ***cu 
lar system of snout disc of swine 

Top I niected va*cutar dermal papillae 
from iJabrou* area (a of tie 47 10 bottom) 
of tnout disc /Vore numerous inuU conical 
vascular lufi» Hollo n Injected vascular 
dermal papillae In pltory area <b of Fit 4“ 
10 bottom) ol anout due Note concentric 
arrangement of pipilhe aurroundlnif each 
hair follicle (See 47 lo for location of 
area* from which specimens were taken.) 
(By Hillmann ) 


ORGAN OF SMELL (ORGANUM OLFACTUS) 

by S Sisson 


The olfactory region Is extensive In correla 
tion with the large size of the olfactory bulbs 
the mucuous membrane here is brown In 
color 


BIBLIOGRAPHY 


Montagna. W 1902. The Structure are! Function of Skin. 2nd rt. 
New York, Academic Pre»» 

Montagna, W and W E. Lot, z. Jr edi I9ft4 The Eptdentii* New 
York Academic Prm 

Sl, *?7 , S , \W1 The Anatomy of the Dome* tic Animal* 2nd *4 
Philadelphia. W B Saunden Co. 



CARNIVORE 


Class 

Mammalia 


Subclass 

Theria 


Infraclass 

Euthena 


Order 

Carnivora 


Suborder 

Flsstpedia 



CANINE 

FELINE 

Infraorder 

Arctoidca 

Aelurotdea 

Family 

Canidac 

Felidae 

Genus 

Canis 

Felts 

Species 

domestica 

domestica 


1424 



CARNIVORE - INTRODUCTION 

by W. H. Riser 


The dog and cat have been inseparable companions to man smce history 
was first recorded in 8000 b c It is speculated that when primitive man emerged, 
the dog protected him and his herds from the predators that roamed the land 
Man’s other companion, the cat, kept rodents from destroying his gram and 
invading his premises (Scott and Fuller, 1965) It is ironic that centuries later, 
and with a world of modem inventions, the dog and cat still remain man’s 
primary security outpost for alerting him to impending danger and keeping out 
vermin 

As man developed a complex social organization, after emerging from his 
nomadic existence to being a master of technical achievement, there was time for 
socializing and the demonstration of skills At this pomt a second group of dogs, 
the sporting group, was developed These dogs were trained to pursue game by 
sight and scent 

A third group, the companion dog with no special skills, was also developed, 
primarily because man was lonely and needed company Since some people like 
to breed and keep strange and grotesque animals, especially dogs, it is not sur- 
prising that many companion dogs often reflect the emotions and even facial 
characteristics and images of their owner (Stockard, 1941) The companion dogs, 
more than the others, were instinctively inclined to cling to man Man can take 
out his frustrations on his dog and the dog seldom fights back After a few pats 
and land words, faith is restored and man and his dog again become close com- 
panions 

The cat has become almost as popular as the dog as a household pet It adapts 
well to family living For the most part it can also be taught to get along well 
with dogs and to live comfortably in a small apartment The cat does not bark, 
create a disturbance or need to be walked, and both sexes improve as pets when 
they are neutered Simple operations are now available to painlessly remove the 
claws with no disfigurement to the animal 

The feline species is represented by a variety of breeds, but selection has 
not changed the anatomical features and size of the animal The differences 
have been limited mostly to such things as color and character of the hair coat, 
tail length, number of toes and the profile of the face The hair coat is changed 
most easily as it varies from almost hairless to several inches in length and from 
straight to curled or rexed The hair color ranges from white to black, with all 
kinds of color combinations, and from solid to spotted and tiger striped Color is 
somewhat sex linked Males display solid or two-colored coats while only females 
may be tn -colored 

As many as 2000 distinct breeds of dogs have been developed in the world, 
in the United States the American Kennel Club recognizes 125 breeds (Am 
Kennel Club, 1968) These have been mostly products of Europe, but other 
countries have produced at least one and sometimes several distinct breeds 
(Lorenz, 1958) As world travel has increased, more and more breeds new to 
America have been brought to this country, especially in the past few years as 
breeds from the Eastern civilizations have been imported for the first time 

The genetic protoplasm of the dog can easily be changed by selection A tiny 
Chihuahua or Pomeranian may mature at less than 1 kg and are midgets when 
compared with the gigantic Great Dane and Irish wolfhound that may mature at 
over 100 kg No other species of mammal differs in weight and size by such order 
of magnitude (100 times) (Stockard, 1941) 


1425 



1426 CARNIVORE -INTRODUCTION 

Equally sinking are the differences in body shape The head may be round 
and acromegalic or have a fiat muzzle (boxer and pug), or it may be long and 
slender with an extended nose (wolfhound and greyhound) The body ranges 
from short (pug), rounded (bulldog) and narrow (whippet), to long (dachshund), 
deep (greyhound), wide (St Bernard) and tapering (Afghan) The legs are long 
and slender in some, short and stocky in others Some toy breeds have thin and 
spindly legs, the chondrodystrophoids have short, heavy, bent and twisted legs 
The tails range from long, slender and straight, to short, heavy and curled, and in 
a few there is no tail at all Hair coats may be of any color or combination of 
colors except green, length and texture range from almost complete absence of 
hair in a few breeds from Mexico, South America and Ceylon, to hair that reaches 
the floor and covers the eyes In spite of this range in size, shape and character- 
istics, the loyal devotion to man is shared by all breeds (Lorenz, 1958, Scott and 
Fuller, 1965) 

Many of the peculiarities of type and structural modifications border on the 
pathological, and a number of diseases encountered in the dog can be directly 
attributed to these variations Examples of this are numerous hydrocephalus in 
those smaller than the ancestral dog, restricted breathing in the brachycephalic 
dog, lateral deviation of the forefoot and intervertebral disc disease in the cbon- 
drodystrophoid, high incidence of tumors, especially twain tumors, in the boxer, 
osteochondritis dissecans of the shoulder and non united anconeal processes of 
the ulna in large and giant dogs, high incidence of foreleg fractures in the 
miniature and toy with long and spindly legs, and hip dysplasia in the large 
breeds, patellar luxation and ischemic necrosis of the femoral bead in the 
miniatures and toys, dystocja in the Yorkshire and Boston terrier, and a variety of 
heart ailments and a high occurrence of bone tumors in large and giant breeds 

This list of anatomical diseases can be extended with each specific breed 
studied Developers of a breed tend to believe that theirs excels all other dogs 
in particular skills and appearance Specially selected dogs and their offspring 
may consistently surpass the ancestral dog in a specific capacity, but none can be 
considered superior in all capacities (Scott and Fuller, 19G5) With few excep 
tions, the special characteristics and skills have been acquired at the expense of 
sacrificing and diluting other capacities, especially when considered from a 
musculoskeletal standpoint 

The dog and cat offer great stimulation to the veterinarian for study and as 
patients for treatment as patients, it is a challenge to restore to and maintain 
them in healthy living, as research subjects, the wide range of body type and 
size and the variation in metabolic function and genetic behavior offer oppor 
tunity to analyze endocrine reactions, tumor ecology, biomechanic function, 
cardiovascular physiology and metabolic differences that cannot be obtained 
elsewhere 


BIBLIOGRAPHY 


American Kennel Club IMS Ibe Complete Do* Book. JUvl»e<! edition. New -York. Doubted** & Compan* Inc. 

Lorenz, K. 1858. Min Meets Do*. Middlesex. England Penjidn Books Ltd. 

1965. Genetic* and the Social Behartor of the Do* Orica* o Unircnilr of Chlceo Presa. 
El ' 4 ° Crtn!C ,Dr D,fWC ~ ^ Philadelphia. £l~ 



CHAPTER 


CARNIVORE 

OSTEOLOGY 

byS. Sisson* 


PART I CANINE 
VERTEBRAL COLUMN 


The vertebral formula is C 7 T 13 L J S J Ca I « 3 
(Fig 48-1) 

Cervical Vertebrae 

(Figs 48-2 through 8 and 15 through 18) 

The cervical vertebrae are relatively longer 
than in the ox and pig The bodies of the typi 
eal vertebrae diminish in length from first to 
last and are compressed dorsoventrally The 
cranial extremity is moderately convex and 
the caudal slightly concave, both are oblique 
The median ndge and lateral grooves on the 
dorsal surface of the body are very well 
marked The second, third, and fourth have 
distinct ventral crests The spinous process of 
the third has the form of a long, low crest, in 
the remainder it is higher, blunt pointed and 
inclined cranially The transv erse processes of 
the third, fourth and fifth project ventrally 
and caudaliy and divide into two branches of 
these, the cranial branch is thin, and the cau 
dal is thick and tuberculate at its free end The 
process of the sixth has two parts, one is an 
extensive quadrilateral plate, which is di 
rected vcntrolatcrally and is ndged on its 
medial surface, the other is short and blunt, 
and is directed laterally and a little caudaliy 
and doreall> The seventh is readily distin- 
guished by its shortness, the length of its 
spinous process and the single transverse 
process The caudal articular processes bear 
tubercles which arc large on the third, fourth 
and fifth 

•WHKi by C R >11 tn port and tcvvrwed (except »kull) by 
N O. CjKMhil 


ATLAS 

(Figs 48-9 through 13) 

The ventral arch of the atlas is narrow cram 
ocaudally and bears a small tubercle caudaliy 
The dorsal surface of the dorsal arch is strong- 
ly convex and rough centrally The lateral 
masses present transverse processes or wings, 
which are wide, flattened and almost horizon 
tal The dorsal surface is rough There is an 
alar notch (incisura alaris) instead of the 
foramen on the cranial border The transi erse 
foramen is present but the spinous process i« 
absent 


AXIS 

(Figs 48-10 through 14) 

The bodj of the axis is flattened dorsoven 
trally, especially cranially The dens is 
and relatively long, reaching almost to the oc 
cipital bone, it is slightly Inclined ’ , 

The articular surfaces which flank it are cor 
dyloid in form and very oblique The ventr~ 
surface is wide, and is divided by a 
crest into two fossae The transverse proc 
esses are single, pointed directed 
and laterally, and perforated by 
large transverse foramina The spinous 
ess is thin and of moderate height, but v 
long, it is prolonged cranially so as to o 
the dorsal arch of the atlas, and is u. 
caudaliy by a tuberosity which is connected l 
tw o crests with the caudal nrtlcular 
Thc cranial notches arc large 

(Text continued an page I w 




FIGURE 48-1. Skeleton of do*; lateral Tiew. 


13B, Last thoracic vertebra, lit 7H. cervical vertebrae. K. aacrtJm. 1L-7L. lumbar vertebrae, 1R-13R. ribs. R kn. cental 
cartilages. S. caudal vertebrae, St. sternum, a, cranium, b. face, c, mandible, d acapula d'. supraspinous fossa, “> 
lnfrajptnous fossa, e, humerus, f, radius, g. ulna, h. carpus, l, metacarpus, k. proximal phalanges, 1, middle phalanges, 
m, distal phalanges, n. sesamoid, p, Ulum, q. pubis, r, ischium, a, femur, t, patella, u, tibia, V. fibula, w, tarsus, x. mett 
tarsus, y, phalanges, 1. spine of scapula, 2. acromion, 3, aupraglenold tubercle, 3\ articular end of scapula, 4, head of 
humerus, 5, greater tubercle of humeros 5', deltoid tuberosity, 6 6‘, eplcondjrles of humerus 7. lateral eplcondyloid 
crest, 7', radial fossa. 8. olecranon. 9, anconeal process of ulna. 10, wing of Ulum, 1 1. body of Ilium. 12 crest of Ilium, 13. 
ventral Uiac spine (coxal tuber), 14. dorsal lilac spines (sacral tuber). 15, lschlatlc spine. 16. Ischlatic tuber, 17. ace- 
tabulum 18. head or femur. 19. greater trochanter. 20. lesser trochanter. 21. third trochanter. 22.23. condyles. 24,25. 
eplcpndyles, 2G, trochlea. 27, tuberosity of tibia, 28, 29. condyles of tibia 30, media! malleolus, 31. lateral malleolus, 32, 
head of fibula, 33 occipital bone, 34. Jugular process, 35, parietal bone, 36. frontal bone, 37, lacrimal bone, 38 zygomatic 
bone, 39, squamous part or temporal bone. 40, maxilla, 40‘. Infraorbital foramen, 41. Incisive bone, 42. nasal bone, 43, ex 
teraal acoustic meatus. 44. canine tooth. 45, masseteric fossa. 46, angular process of mandible (From EHenberger, 1908 ) 



FIGURE 48-2 (left). Third cervical vertebra of dog; left lateral view. 


1, cranial and 2, caudal ends of body, 3 articular processes, 4, spinout process 5 6, transverse process, 7. transverse 
foramen. 

FIGURE 48-3 (middle) Fourth cervical vertebra of dog, left lateral view. 

1, Cranial and V. caudal ends of body 2, 2 articular processes. 3. transverse process, 4, spinous process 
FIGURE 48-4 (right). Seventh cervical vertebra of dog; caudal view, 
t. Body, 2, capitular facet for first rib '3, transverse process, 4, pedicular notch, 5, 5’, articular processes, 6, spinous 
process 
1428 , 


29 










48-CARNIVORE OSTEOLOGY 


FIGURE 48-10 Lateral view of 
atlas and axis of dog 

Note that the dens of the axis forms 
the floor of the vertebral canal at the 
level of the atlas and that excessive flex 
ion of the atlantoaxial articulation can 
force the dens against the spinal cord. 
(From Hare 1961a.) 



Sptnoua process 
Dorsal arch ■ 
Intervertebral for 


Occipital condyle 
Dens 



Caud art process 
Sptnous process 

Intervertebral for 
Transverse process 
Caud extremity 


Transverse process 
(cran. spicule) 


Craiu articularfovea 


FIGURE 48-11 Labelled traclnt of Figure 48-10 
(From Hire 1901a.) 


1432 


CARNIV ORE 



Thoracic Vertebrae 

(Figs 48-15 through 19) 

The todies of the thirteen thoracic verte- 
brae are wide and compressed dorsoventrally 
especially at each end of the region Their con 
vex cranial surfaces are depressed in the mid 
die The caudal facets for the heads of the nbs 


are absent on the last two or three The trans- 
verse processes resemble those of the horse 
They bear mamillary processes except at the 
cranial end of the region The facets for the 
tubercles of the ribs are large and concave in 
the -cranial part of the series and become 
smaller and slightly convex farther caudad- 
The last three have accessory processes also 



48-CARNIVORE OSTEOLOGY 



FIGURE 48-14 Axis of dog, left lateral view 

1 Dens 2 cranial articular process 3 caudal end of 
body 4 arch 5 caudal pedicular notch 6 transverse 
process 7 transverse foramen 8 caudal articular 
process 9 spinous process 


The first three or four spinous processes are 
about equal in length Caudal to this they be 
come gradually shorter to the tenth and then 
remain equal. The caudal slope is most marked 
in the ninth and tenth The eleventh is prac 


1433 

txcally vertical, and the last two incline slight 
ly cramad 

Lumbar Vertebrae 

(Fig 48-20) 

The bodies of the seven lumbar vertebrae 
are decidedly flattened dorsoventrally, and m 
crease in width from first to last The length 
increases to the sixth The transverse proc- 
esses are plate hke and are directed cramad 
and ventrad Their length increases to the 
fifth and sixth They form no joints with each 
other or with the sacrum Their extremities 
are enlarged, with the exception of the last 
The accessory processes project caudally over 
the caudal notches of the first five The cram 
al articular processes are large, are com 
pressed laterally, and bear mamillary proc- 
esses The spinous processes are broad 
ventrally, narrower dorsally and, with the ex- 
ception of the last, incline a little cranially 
Their height diminishes caudal to the fourth 


Figure 48-15 Cervical vertebrae five 
to seven and thoracic vertebra one of dog 
lateral view 

Note the size and direction of the interver 
tcbral space between the bodies of cervical ver 
tebrae six and seven and the plate-like trans- 
verse process of cervical vertebra six (From 
Hare 1961a) 






FIGURE 48-19 (left). Fourth thoracic Yertebrs of dog; left view. 


I. Body, 2, 2 , costal facets of body, 3. caudal pedicular notch. 4, 4', articular procease*. 5 transverse process, 0, facet 
for tubercle of rib, 7, mamillary process 8, spinous process. 

FIGURE 48-20 (middle). Fifth lumbar Tertebra of dog: dorsal view. 

I, Cranial end of body. 2. spinous process. 3, 3 . ortlcular processes 4. transverse process. 5. accessory process, 6, 
groove for lumbar spinal nerve 

FIGURE 48-21 (right). Sacrum of dog; ventral view. 

Ml til. Bodies of vertebrae. 1. 2. sentral sacral foramina, 3.4. transverse lines, S, cranial end of body of first sacral ver 
tebra G 6 . cranial articular processes. 7. 7 . wine*. 8 caudal end of body of last sacral vertebra 9. 9 , caudal articular 
processes 10, sacral canal. 1 1, spinous process 12. 12 , transverse processes, 13, auricular surface 



CARS I\ORF 


1436 

tensive face almost directly latcrad and bear 
an auricular surface on the ventral part The 
cranial surface of the body of the first vertebra 
is extensive is depressed in its middle and 
bears a prominent lip ventrally The cranial 
articular processes are large and have exten 
sive slightly concave facets which face dor 
somedially The caudal articular processes 
are small The transverse processes of the last 
vertebra project caudally and may articulate 
or fuse with those of the first caudal The 
sacral canal is strongly compressed dorso- 
ventrally 


Caudal Vertebrae 


The caudal (coccygeal) vertebrae are fully 
developed in the cranial part of the region 
Usually the arch is complete in the first six 
The first three or four have well developed ar 
ticular processes at each end Caudal to this 
the caudal processes quickly disappear and 
the cranial ones become non articular and 
gradually reduced in size The transverse 
processes of the first five or six are relatively 
large caudal to this they quickly disappear 
Hemal arches (or chevron bones) in the form 
of a V or Y occur ventrally at the interccntral 
junctions of the third fourth and fifth usual 
ly They transmit the middle caudal artery 
which passes between pairs of ventral tuber 
cles further caudad 


VERTEBRAL CURVES 

A gentle curve convex ventrally is formed 
by the cervical and the cranial parts of the 
thoracic region The caudal thoracic and the 
lumbar vertebrae form a second curve con 
cave ventrally The sacral promontory is well 
marked The sacrum and the cranial part of 
the caudal region constitute a third and more 
pronounced curve concave ventrally In long 
tailed dogs the sacrocaudal region is some 
what S shaped 

Variations Numerical variations are not common ex 
cept in the caudal region The number of thoracic vertebrae 
may be twelve or fourteen, with or without compensatory 
change in the lumbar region Girard (Sisson 1921) re 
corded a case with eight lumbar and the usual number of 
thoracic vertebrae Six lumbar with fourteen thoracic ver 
tebrae have been seen. The first caudal sometimes unites 
with the sacrum 


THORAX 


The thorax is distinctly barrel like and is not 
decidedly compressed crantally hke that of 
the horse and ox The crania! aperture (inlet) 
is oval and is relatively wide because of the 



FIGURE 48-22. Sternum of dog dorsal new 

I Manubrium 2 body of second stemebra 3 third cos- 
ta! cartilage 4 Interstemebral cartilage 5 5lh rib 6 cos- 
tochondral articulation 7 seventh stemebra 8 xiphoid 
process 9 xiphoid cartilage 


marked curvature of the first pair of ribs and 
cartilages 


Ribs 

Thirteen pairs of nbs are present of which 
nine are true or sternal and four false or aster 
nal They are strongly curved narrow and 
thick. Those in the middle of the series are the 
longest The first eight or nine increase in 
tvidth In their ventral part 77ie last rib is 
usually floating The heads of the last two or 
three articulate with only one vertebra. The 



FIGURE 48-23 Sternum of dog lateral view 


1 Manubrium 2 body of second stemebra 3 third cos- 
ta) cartilage A sternocostal articulation 5 fifth rib 6 
costochondral articulation 7 seven h rib 8 xiphoid carti 
lage 


48 -CARNIVORE OSTEOLOGY 


1437 


costal cartilages are long, and curve ventrally 
and cranially, the length and curvature of the 
first pair are striking special features 

Sternum 

v (Figs 48-22 and 23) 

This is long, is laterally compressed, and 
consists of eight stemebrae, which fuse only 


in exceptional cases and m extreme old age 
The first segment, the manubrium, is the 
longest, its cranial end is blunt pointed and 
bears a short conical cartilage It widens at 
the point of articulation of the first pair of 
cartilages The last segment, the xiphoid 
process, is also long, is thinner than its pred- 
ecessors, and is wide cranially and narrow 
caudally, where it bears a narrow xiphoid car- 
tilage. 


APPENDAGES 


BONES OF THE THORACIC LIMB 

(Table 48-1) 

The thoracic Umb of the carmvoTe is com 
posed of four chief segments the thoracic 
girdle (clavicle and scapula), the arm (humer- 
us), the forearm (radius and ulna), and the 
manus (carpus, metacarpus, phalanges and 
sesamoid bones) 


Thoracic Girdle (Shoulder) 

(cingulum membri tharacici) 

CLAVICLE 

The clavicle is a small, thin, irregularly tn 
angular bony or cartilaginous plate It is ero 
bedded m the brachiocephalicus, cranial to 
the shoulder joint and forms no articulation 
with the rest of the skeleton 


SCAPULA 

(Figs 48-24 through 33) 

The scapula is relatively long and narrow 
The spine increases gradually in height dorso- 
ventrally, and divides the lateral surface into 
two nearly equal fossae (supraspinous and 
mfraspinous) Its free edge is thick and rough 
dorsally, and at the ventral part is thin and 
bent caudally The acromion is short and blunt, 
and is opposite the nm of the glenoid cavity 
The subscapular fossa is very shallow and is 
marked by rough lines The rough area dorsal 
to it for the attachment of the serratus ven- 
tralis muscle, the facies serrata, is large and 
quadrilateral cranially, narrow and marginal 
caudally The cranial border is thin, strongly 
convex and sinuous The caudal border is 
straight and thick The dorsal border is con- 
vex and thick, and bears a band of scapular 
cartilage The cranial angle is opposite the 
first thoracic spme and is rounded The caudal 


TABLE 48-1 Anatomical Epiphyseal Closure Times for Thoracic Appendage of Dog 


Rone 

Baum and ZiMitm. 0951) 

LsatmE (1897) 

Scapula 

6-8 mo 

6-8 mo. 

Humerus 

Proximal 

IV* yr 

- 13 mo 

Distal 

6-8 mo 

6-8 mo 

Radius 

Proximal 

6-8 mo 

6-8 mo. 

Distal 

Ulna 

Proximal 

16-18 mo. 

16-16 mo 

15 mo 

15 mo 

Distal 

15 mo 

IS mo 

Metacarpal HI 

Proximal 

before birth 


Dista} 

5-6 mo 

5-6 mo 

Proximal phalanx 

Proximal 

5-6 7710 . 

5-6 ma 

Distal 

before birth 


Middle phalanx 

Proximal 

5-6 mo 

5-6 mo 

Distal 

before birth 


Distal phalanx 

- 

_ 



1438 


CARNIVORE 



FIGURE 48-24 Left scapula of dog lateral view 


Cort&ije 



FIGURE 48-25 Right acapnia of dog medial view 




shoulder of 4 month-old female Scotch Collie 

Note centers of ossification for supra glenoid tubercle 
and proximal epiphysis of humerus. (From Hare 1 959a.) 

FIGURE 48-27 Labelled tracing of Figure 48-26 
(From Hare 1959a.) 


48-CARNIVORE OSTEOLOGY 


1439 


FIGURE 48-28 Right shoulder of II month-old male Ger 
man Shepherd caudocramal view 

(From Hare 1959b ) 




(From Hare 1959b) 





48— CARNIVORE OSTEOLOGY 


1441 



FIGURE 48-32 Right shoulder of 9 month old female German Shepherd mediolateral view 


Note that part of the epiphyseal cartilage is still present between the proximal epiphysis and dlaphysis of the humerus 
(From Hare 1959b ) 


undivided greater tubercle (lateral tuberosity) 
is placed well craniad and extends a little 
proximal to the level of the head The lesser 
tubercle (medial tuberosity) is small The m 
tertubercular groove is undivided and is dis 
placed to the medial side by the cranial exten 
sion of the greater tubercle The distal end 
may be regarded as a condyle It bears an 
oblique trochlear articular surface for articu 
latlon with the ulna, the literal part of which 
Is the more extensile and is faintly grooved, 
and a capltulum for articulation with the 
radius The epicondyles arc prominent The 


radial and olecranon fossae often communi 
cate through a large supratrochlear foramen 
The proximal end unites with the body at 
about one year, the distal at six to eight 
months 


Forearm 

(Figs 48-36 through 44) 

The two bones of the forearm are relatively 
long, and articulate with each other at each 
(Text continued on page 1445 ) 




48 -CARNIVORE OSTEOLOGY 


1443 



FIGURE 48-36 Right humer- 
oradioulnar joint of 12 month- 
old female German Shepherd, 
mediolateral view 

Note that although the joint is 
partly flexed the anconeal process 
of the ulna Is still situated be 
tween the medial and lateral epi 
condylar crests of the humerus 
This illustrates that the joint 
should be fully flexed before at 
tempting to reduce a dislocation 
of the humeroradloulnar joint 
(From Hare 1959b) 



(From Haw 1959b.) 


1444 


CARNIVORE 



FIGURE 48-38 Right humeroradioulnar joint of 12 
monttvold Temple German Shepherd eranlocaudal view 

(From Hare 1959b) 


Olecranon /ossa 
Anconeal process 
Medial epieondyle 
Trochlea 

Coronotd process 


Me i al i rominence 
Lateral prominence 

Olecranon 

Trochlear notch 
Lateral cpicomlyle 
Cap t tlum 
Lateral tuberosity 


FIGURE 48-39 Labelled tracing of Fig 
lire 48-38 


(From Hare 1959b) 



1445 


48— CARNIVORE OSTEOLOGY 



FIGURE 48-40. Left radius and ulna of dos; me- 
dial view. 


a. Rough area for attachment of blce P* 1 ^S¥Ljjf 
brachlalis; b, groove for tendon of abductor dig! 


end in such a manner as to allow slight move- 
ment. A narrow interosseous space separates 
their shafts. 

RADIUS 

The radius is flattened craniocaudally and 
increases in size distally. The body forms two 
curves, so that it is convex dorsally and medi- 
ally. The dorsal surface is convex in both di- 
rections and is marked in its distal half byj a 
groove for the abductor digiti I longus. The 
caudal surface presents the nutrient foramen 
In its proximal third, and bears a rough line 
laterally for the attachment of the interos- 
seous ligament The proximal end or bead is 
relatively small, and is supported by a distinct 
neck. It bears a concave surface for articula- 
tion with the humerus, and a convex marginal 
area, the articular circumference, caudally for 
the ulna. The radial tuberosity is small; proxi- 


mal to it is a large lateral eminence and distal 
to this a rough eminence. The distal extremity 
is much wider, forming a trochlea. It has an 
extensive concave carpal articular surface. 
Its medial border projects distally, forming 
the styloid process of the radius. Laterally 
there is a concave facet, the ulnar notch, ior 
articulation with the ulna. Dorsally there are 
three distinct grooves for the extensor ten- 


ULNA 

The ulna is well developed, but diminishes 
in size distally. It crosses the caudal surface 



FIGURE 48-41. Left forelimb of 55-day-old female 
Scotch Collie; mediolateral view. 

Note the following center* of ossification: trochlea and 
capitulum and medial eplcondylc of humerus; olecranon 
and distal epiphysis or utna; proximal and distal epiphyses 
of radius; and epiphysis and diaphysls of accessory carpal 
bone (From Hare. 1959a.) 


1446 


carnivore 


of the radius medlolaterally The bod} js 
large and three sided in its proximal two 
thirds smaller and more rounded distally Its 
cranial surface is in general, rough The nu 
tnent foramen is near the proximal end A 
vascular groove descends from Rand indicates 
the course of the interosseous artery The 
proximal end Is relatively short It Is concave 
and smooth medially, convex and rough Zat 
erally The olecranon is grooved and bears 
three prominences, of which the caudal is 
large and rounded The trochlear (semilunar) 
notch is wide distally, and completes the sur 
face for articulation with the trochlea of the 
humerus Distal to it is a concave surface, the 
radial notch, which articulates with the caudal 
part of the head of the radius, distal to this is a 
fossa which receives a tuberosity of the radi 
us The distal end or head, is small and is re- 
duced to a blunt point, the styloid process it 
articulates with the ulnar carpal bone distally, 
and has a convex facet on its dorsomedial as 
pect for the radius The proximal end of the 
radius unites with the body at six to cis»ht 
months, the distal at about one and a half 
years of age The olecranon and the distal end 
of the ulna fuse with the rest of the bone at 
about fifteen months 

Manus 

(Figs 48-41 through 44 and 46 through 5l) 


CARPAl BONES 

(Fig 4 8-45) 

The carpus comprises seven bones— three 
in the proximal row and four in the distal The 
numerical reduction in the proximal row is 
apparently due to the fusion of the radial and 
intermediate, constituting a large bone, the 
intermedioradial, which articulates with al 
most all of the distal surface of the radius and 
with the bones of the distal row It projects 
prominently on the palmar surface of the car 
pus The ulnar carpal is long, it articulates 
with the radius and ulna proximally and the 
accessory palmarly, distally it rests on the 
fourth carpal and is prolonged distally, to 
articulate with the fifth metacarpal also The 
accessory carpal is cylindrical, and fs con 
stricted in its middle and enlarged at each end , 
the dorsal extremity articulates with the ulna 
and ulnar carpal bone The first carpal is the 
smallest bone of the distal row, it articulates 
with the second carpal laterally and the first 
metacarpal distally The second carpal is 
wedge shaped the base being palmar, its 
proximal surface is convex, and Its distal is 
concave and rests on the second metacarpal 
The third carpal is somewhat like the second, 
its distal surface is concave and articulates 
chiefly with the third metacarpal The fourth 
carpal is the largest of the row, it articulates 
with the fourth and fifth metacarpals Two 


Medial epicondyle . S' / 

/ 

Trochlea 

Ofecranon.^-.^YsW ( 

— Capituium 

Proximal 

epiphysis (radius)-- 

.Distal epiphysis (radius) 

Distal epiphysis (utna)^ \\v\ 

/ .Radial and intermediate 

Epiphysis ( accessory X. \ \S, 

A / / y Carpal t 

Ulnar 

/ / Carpal l 

Carpal 6 ~~ 

— Epiphysis (me l ) 

Carpal 3 

Epiphysis (me 2 ) 

Palmar — ‘S'ltnoids — — - — — 11 

— 


Epiphysis (prox ph 3) 


fxZ* Epiphysis (mid ph i) 


FIGURE 48—12 Labelled tracing of Figure 48—41 
(Frt>m Hare 1959a.) 




1447 

48 -CARNIVORE OSTEOLOGY 

FIGURE 48-43 L-ft forel.mb of 55 day-old female Seo.eh Coll.e, 
cramocaudal view. 

Note the following centem of tBsi^™ 

t^tS&z^*™^***** ** pto, “ 5cs 

of digits 11 v (From Hare. 1959a) 



Epiphu*i* f ,ne 

Palmar ersamoida 


FIGURE 48-44 Labelled tracing of Figure 48-43 
(From Hare 1059a.) 


small bones or cartilages may be £>und 
palm ir surface at the junction of the two » row ■ s, 
and a third small bone articulates with the 
medial side of the Intcrmcdioridl'u 


WE7ACARPAI BONES 

Five metnrarpal bones arc prrvcnt The 
first Is much the shortest the third and fourth 
art* the longest, and arc about one fifth lon 
than the second and fifth The fifth Is « 
widest at the proximal end and Is silgntt 
shorter titan the second Tltrv are close to- 
gether above, but diverge somewhat dl*t my. 
the best Is separated from the second t>v a 
comidf table Intenwswnis space They are so 


arranged as to form a cons ex dorsal surface 
and a concave palmar surface, sshich cor- 
responds to the hollow of the palm of the hand 
in man Each consists of a body and tsso ex- 
tremities The body is compressed dorsopal- 
tnarly In the third and fourth it Is almost four 
sided, in the second and fifth three sided, in 
the first rounded The proximal ends (bases) 
articulate with each other and with the cor- 
responding carpal bones The carpal articular 
surface formed b) them is concav c from side 
to side, coni, ex dorsopnlmarly The distal ends 
hair articular surfaces of the nature or a 
head, but bear a sagittal ridge on the palmar 
aspect except the first, which is grooved 
Ossification is complete at five or six months 
of age 


CARNIVORE 



The digits are spread. C palmar (proximal) sesamotds 
C.a accessory carpal (very small part visible) C r + L In- 
lennedioradjal carpal C u ulnar carpal Cl CJ2 C.3 C 4 
first to fourth carpal bones I distal end of Interosseous 
space Me.l metacarpal bone 1 Me V metacarpal bone V 
P 1 P 2 P 3 pro xima l middle and distal phalanges of 
fifth digit P 1 P.3 proximal and distal phalanges of first 
digit R distal end (trochlea) of radius S dorsal sesamoid. 


DIGITS OF THE MANUS 

The digits have three phalanges each ex 
cept the first which has two The third and 
fourth digits are the longest the first is very 
short and does not come in contact with the 
ground in walking The proximal phalanges of 
the chief digits have four sided shafts which 
are slightly curved dorsally The proximal end 
of each has a concave surface for articula 
tion with the metacarpal bone, and is deeply 
notched palmarly The distal end or head has a 
trochlea for articulation with the middle 
phalanx, and depressions on each side for 
ligamentous attachment The middle pha 
langes are about two-thirds of the length of 
the proximal phalanges The proximal aitjtm 
lar surface consists of two cavities separated 


by a sagittal ridge The distal extremity is 
wider and flatter than that of the proximal 
phalanx There is no middle phalanx on the 
first digit The distal phalanges correspond in 
general to the form of the claws The base has 
an articular surface adapted to the middle 
phalanx and is encircled by a collar of bone 
{crista ungutculans) The solar surface bears 
a flexor tubercle, and on each side of this is a 
foramen The ungual process is a curved rod 
with a blunt pointed free end It is rough and 
porous Its base forms, with the collar previ 
ously mentioned, a deep groove, into which 
the proximal border of the claw is received 
The two phalanges of the first digit resemble 



FIGURE 48-46 Right forelimb of 40-day-old ta- 
male Scotch Collie craniocaudal new 

Note the following centers of ossification trochlea and 
capitulum of humerus {the capltulum may have two 
centers the trochlea has one center and the medial «Pi- 
condyle has a separate center) proximal and distal epi 
physes of radius nine centers for the carpal bones prox 
final epiphysis for metacarpal I but distal epiphyses for 
metacarpal* II V (From Hare I So 9a.) 


48 -CARNIVORE OSTEOLOGY 


2449 


FIGURE 48-47 Labelled 
tracing of Figure 48-46 on 
page 1448 

(From Hare 1959a.) 


Lateral condyle ■ 
Proximal epiphysis (radius)' 
Accessory < 

Ulnar 

Carpal U 

Epiphysis (me S) 
Epiphysis (prox pti S) 



Medial condyle 

Distal epiphysis 
(radius ) 

Intermediate 


FIGURE 48-48. Right paw of 10-monlh-old male 
Scotch Collie, medlolateral view 

Note that there are one dorsal and two palmar sesa- 
moid* at each metacarpophalangeal Joint except that of 
the first digit where there Is one dorsal sesamoid although 
this is frequently absent and only one palmar sesamoid. 
(From Han* 1959b) 


1450 


CARNIVORE 


Giootefot m ext 
carp radiahs 



D stal phalanx 2 
Ungual crest 
Extensor tubercle 


FIGURE 48-49 Labelled 
tracing of Figure 48-48 on 
page 1449 
(From Hare 1959b.) 


FIGURE 48-50 Right paw of 13 month-old male 
German Shepherd dorsopalmar view 

Note sesamoid bone of abductor digltl 1 longus it should 
not be mistaken for a chip fracture The flexor digliorum m- 
perficialis is inserted into the medial and lateral tubercles of 
the middle phalanges (From Hare 1959b.) 


Styloid process (ulna) 


48 -CARNIVORE OSTEOLOGY 

\ !\ III Ml/I Groove for m ab digit* l longus 

1 Uii ill / Styloid process (radius) 


Sesamoid bone of abductor 
digit! / longus 


Metacarpal 5 


Metacaipal k 


Metacarpal 1 ■ 
Palma) sesamouls 


Luteial tubeicle 


Ungual eiest • 
Ungual places* 



'Metacarpal 1 
s Prox phalanx 1 
S Metacarjjal 2 


Medial tubercle 


Middle phalanx U 


Distal phalanx 3 


^FIGURE 48-51 Labelled tracing of Figure 48-50, on page 1450 
(From Hare 1959b ) 


in arrangement the proximal and distal pha 
langes of the other digits Ossification is com 
plete at five or six months 
The sesamoid bones Nine palmar sesa- 
moids are usually present Two are found at 
each metacarpophalangeal joint of the chiet 
digits They are high and narrow, they articu- 
late with the distal end of the metacarpal bone 
dorsally and have a small facet on the base for 
the proximal phalanx On this joint of the first 
digit there is usually a single, flattened, sesa- 
moid, exceptionally, two are present The dis- 


tal palmar sesamoids remain cartilaginous A 
nodular dorsal sesamoid occurs m the capsule 
of the metacarpophalangeal .joints, and car- 
tilaginous nodules are found m a similar posi- 
tion in connecuon with the joints between the 
proximal and middle phalanges 

bones of the pelvic limb 

(Table 48-2) 

The pelvic limb, like the thoracic, consists of 
four segments the pelvic girdle, thigh (femur 


TABLE 48-2 Anatomical Epiphyse s Closure Times non Pei-v.c Appendage of Doo_ 


Dbuni AND ZiHMEBC (1951) 


Ilium ischium pubis 
Femur 
Proximal 
Distal 
Tibia 
Proximal 
Distal 
Fibula 
Proximal 
Distal 
Calcaneus 

Bones distal to tarsus same as distal to carpus 


ss|&. 3° HI 





48 -CARNIVORE OSTEOLOGY 


1453 


FIGURE 48-53. Right os coxae 
of dog; lateral view. 

1, Gluteal surface of Ilium; 2, crest 
of ilium, 3, sacral tuber; 3', cranial and 
3*. caudal dorsal iliac spines; 4, cranial 
ventral lilac spine {coxal tuber), 5, body 
of ilium; 6, nutrient foramen, 7, greater 
ischiatic notch, 8, ventral gluteal line, 
9, iliopubic eminence, 10, tubercle for 
psoas minor. 11, 1 1\ cranial and caudal 
branches of pubis; 12, articular (lunate) 
surface of acetabulum, 12', acetabular 
fossa; 13, obturator foramen; 14, ischia- 
tic spine; 15, lesser ischiatic notch; 16, 
body and 16', ischial branch, 17, ischia- 
tic tuber. 



which terminates at a tuberosity cranial to 1 i 
acetabulum. The greater ischiatic notch is 
elongate and very shallow. 


Ischium 

The ischium has a twisted appearance, 
owing to the fact that its acetabular part is 
nearly sagittal while the caudal part is almost 
horizontal. The two bones also diverge cau- 
dally and the tubera are flattened and evertea. 


The ischiatic spine is low and thick; its caudal 
«nrt iK marked by transverse grooves and has 
r?rimTnent laterS lip. The lesser ischla«c 
notch is shallow, smooth and rounded for the 
nassace of the tendon of the obturatonus in- 
femil The ischial arch is relatively small and 


>ubis 

The symphyseal part of the pubis is thick, 
md fuses late with the opposite bone. 


FIGURE 4B-51. Left os 
coxae of dog; ventral view. 

(From Hare. 1960a.) 


Cranial ventral iliac spine 
Caudal ventral iliac spine 
Auricular surface 
Tubercle for psoas minor 
Ischiatic spine 



Iliopubic eminence 
Cranial rim 
Dorsal rim 
Lunate surface 
Acetabular fossa 
Caudal nm 
Acetabular notch 


A 


Pubic symphysit 



1454 


CARNIVORE 


Acetabulum 

The acetabulum is about twice as far from 
the coxal tuber as from the ischiatic tuber. 
The acetabular fossa is deep, and is bounded 
medially by a flat plate of bone; its floor is so 
thin as to be translucent There is a small 
acetabular notch caudally. 


conjugate (diameter) is the longer. The cavity 
is narrowest between the acetabula, and very 
wide caudally. The floor is concave and rela- 
tively narrow cranially, wide and flat caudally. 


Thigh 


Obturator Foramen 

The obturator foramen resembles in outline 
an equilateral triangle with the angles 
rounded off. 

Union of the three parts of the os coxae has 
usually taken place at six months, but the 
epiphyses of the ilium and ischium do not 
fuse with the main part of these bones till 
about the end of the second year. 

PELVIS 

(Figs. 48-55 through 59) 

The cranial aperture (inlet) of the pelris is 
very oblique. It is almost circular In the fe- 
male, but in the male It is elliptical and the 


FEMUR 

(Figs. 48-130 through 63) 

The femur is relatively much longer than in 
the horse or ox. The body is regularly cylin- 
drical, except near the extremities, where it is 
wider and compressed craniocau dally. It is 
strongly curved in its distal two-thirds, con- 
vex cranially. The facies aspera is flattened 
transversely, is narrow in the middle, and 
widens toward each end. It is bounded by two 
rough lines ( labja laterale and mediate ), 
which diverge toward the extremities. The 
third trochanter is small. The supracondyloid 
fossa is absent. There arc two supracondyloid 
tuberosities, the medial one being small. The 
nutrient foramen is in the proximal third of 
the caudal surface. The head is little more 
than a hemisphere and has a shallow fovea 
( Text continued on page J 458.) 





4 8 — CARNIVORE OSTEOLOGY 


1455 


I hue rust 
Cut mill lent ml time a/iiiir 
Caudill initial iliac K/imr 
(ilutial Kin lace' 
Tulnulc tiu iisouh iii nun 

llutlinlm (iimu net 
( mum! line 

Dm s al inif 
An lulnthii fi\ 

Ant aim la i notdi 
( a mini inn 
Inch tut ic tfiint 
Oltnmtoi tm amt n*Tj 



Sat i n lu 

Saninhiit aiticulatmn 
C initial i n It but 1 
Fin ttt tain! is 
Miisritlai hut 
■Ti orbit lift i mu tin 
lufciiiticItttuU in tiist 
Tmcbtniltiic fossa 
Luuatt sin tact 
Tint ha aft i U i tins 
Tim hunti > in nun 
I st hint ir tain i 
f srh hi tic anh 


FIGURE 18-3G 


I abetted tracing of Figure 18-53 dn page 1454 
i From Hare 19G0i ) 



The ilium Ischium pul Is rnd acetabulum have not jet united with eti 
trochanters of the femur united with the duphysU (from Hare 1960b ) 


nor ime tne Head irreatera 





1456 


CARNIVORE 



The iliopubic llioischlal and ischlopubic articulation* are the cartilaginous Joint* between the ilium Ischium and pubis 

(From Hare 1900b) 



FIGURE 48-59 Pelm and 
coxal articulation* of 6-month 
old Scotch Collie ventrodorsal 
view 

A One center of ossification for 
lschlatlc arch R center of ossifi 
cation for wedge shaped bone that 
forms pan of lichiatic arch at pet 
vie symphysis C ossification 
center of Ischfatic tuberosity D 
epiphyseal cartilage between 
greater trochanter and diaphysis 
of femur E epiphyseal cartilage 
between head and diaphysis of 
femur F ossification center for 
iliac crest (From Hare 1960b) 



48— CARNIVORE OSTEOLOGY 


1457 


Greater Head 



FIGURE 48-60. Right femur of dog; cranial view. 


Head 


Neck 

Lower ttochimtei 


Trochanteric 

fossa Greater 
, trochanter 



Medial 

condyle 


FIGURE 48-61. Right femur of dog; caudal view. 


1, 2, sesamoid bones. 


FIGURE 48-62. Proximal end 
of right femur of 7V*-month-old 
female German Shepherd; medio- 
lateral view. 

(From Hare, 1960b ) 




1458 


CARNIVORE 



caudal and lateral to Its center The neck is 
well defined The major trochanter does not 
extend as high as the head, a thick ridge runs 
from its cranial surface to the neck The 
minor trochanter has the shape of a blunt 
tuberosity The trochanteric fossa is round and 
deep The ndges of the trochlea are practically 
sagittal in direction and are almost similar 
The intcrcondyloid fossa is wide Just proxi 
mal to each condyle caudally there is a facet 
for articulation with the sesamoid bone which 
is developed in the origin of the gastrocnemius 
muscle Union of shaft and extremities takes 
place at about one and a half years 


PATEllA 

The ‘patella U long and narrow The free 
surface is convex in botli directions The ar 


ticular surface is convex from side to side and 
slightly concave proximodistally 


Leg 

(Figs 48-70 through 73) 

TIBIA 

The tibia is about the same length as the 
femur The body forms a double curve, the 
proximal part is convex medially, the distal 
part laterally The proximal third is prismatic, 
but is compressed laterally and is long cranio 
caudally The remainder is almost regularly 
cylindrical The cranial border (crest) is short 
but very prominent The nutnent foramen is 
usually in the proximal third of the lateral 
( Text continued on page 146 2 ) 


48- CARNIVORE OSTEOLOGY 


1459 


1 / yitstuH iicnnuH 

Medial and lateral « 
setanwids nf j 
pastrocnemtits 

Ti ochlea 
Putella 
E> ten hoi ttusiu 
hiteirondylai eminence 
Ciu mat mteicomlifiai «if« 
Patillai It gam tut 
Tiliinl tubciOHity 
Ciumul nuo gin of tibia 



I utt ml xtipiaiondylm 
tuba unity 
■Medial cn udyh 
Lati ml ( niidyh 
PopUteal It/nifih node 
Caudal iiitotondylui aieu 
■San nioul of paplifcii't 
Medial tandylt 
Lati ml toiidyle 
Popliteal notch 
Hi ad ( fibula) 

[jilt i ml s aphenoiiK mn 


FIGURE 18-65 I abclled tracing of Figure 48-64 
(From Hare 19G0a ) 


FIGURE 48-66 Right stifle joint of 1-ycar old 

female German Shepherd, caudocranial view 

The apparently large space between the condyles of 
the femur and those of the tibia is due to the joint 
being in extension and to the presence of menisci 
which are radiolucent The sesamoid bone of the poph 
teus is not seen in this view because its image is of in 
sufficient density to show through that of the lateral 
condyle of the tibia. (From Hare 1960a.) 




1460 


CARNIVORE 



(From Hare 19GOa_) 



FIGURE 48-68 Right femorotibial articulation 
female German Shepherd caudocramal 


of 3 month-old 

view 


(From Ilare 1960b) 



48-CARNIVORE OSTEOLOGY 


1461 


Patella • 

Medial sesamoid 
of gastrocnemius 
Proximal epiphysis (tibia, 
Ttbtal tuberosity 

Diaphy sis (tibia) 



Diaphysis (femur) 

Lateral sesamoid 
'of gastrocnemius 

Distal epiphysis (femur) 

, Proximal epiphysis (fibula) 
.Diaphysis (fibula) 


FIGURE 48-69 Labelled tracing of Figure 48-68. 
(From Hare 1960b ) 


Intercondylar eminence 


Tuberosity 


Cranial border 



Body of tibia 


- Head of fibula 


■ Interosseous space 



Medial 

malleolus 


- Lateral malleolus 


FIGURE 48-7<L_JRight tibia and fibula of dog, 
cranial new 


FIGURE 48-71 Right tibia and fibula of dog, 
caudal new 


i 



1462 


CARM\ ORF 



border The tuberosity is not grooved, but 
bears a distinct mark where the patellar 11 ga 
ment is attached There is a small facet for the 
fibula on the caudolateral part of the lateral 
condyle and a small sesamoid bone m the 
tendon of origin of the pophteus is in contact 
with the caudal angle of the latter The distal 
end is quadrangular and relatively small The 
articular grooves and ndge are almost sagit 
tal There is a facet laterally for articulation 
with the fibula. Also present are a vertical 
groove medially and a shallower one caudally 
—both for tendons The proximal end unites 
with the body at about eighteen months, the 
distal at fourteen or fifteen months 


FIBULA 

The fibula extends the entire length of the 
region It is slender and somewhat twisted 
and is enlarged at either end The proximal 


part of the body is separated from the tibia by 
a considerable interosseous space but the 
thstal part is flattened and closely applied to 
the tibia The proximal extremity is flattened 
and articulates with the lateral condyle of the 
tibia The distal end is somewhat thicker and 
forms the lateral malleolus It articulates me 
diafly with the tibia and the talus Laterally it 
bears two tubercles y 


Pes 


TARSAL BONES 
(Figs 48-74 through 80) 


* , /.‘JT composes seven bones The 

talus (tibial tarsal) consists of a bodv nprlc 
and head like the bene m £ tody 
presents a proximal trochlea for articulation 



48 -CARNIVORE OSTEOLOGY 


1463 


Diaphysis (fenun). 
Distal eptphys is (jenmt ) 
Patella 

Piouinal epiphysis (tibia) 1 
Tibial tubeiaxity' 
Diaphysis (tibia) 
Distal epiphysis (fibula) 
Distui epiphysis (tibia)- 
Tala- 
Centialtm sal 

Thud taisul 

M eta tui sals laud* 


Medial 4 



Lateral 1 Sesamoid bones 
j of gastrocnemius 


Sesamoid of popliteus 

Proximal epiphysis 
(fibula) 

Diaphysis (fibula) 
Medial malleolus 
Epiphysis (calcaneus) 
'Calcaneus 
i F ourth tat sal 
'Second tarsal 
First taisal 
Metatarsal I 
Metataisals2and5 


FIGURE 48-73 Labelled tracing of Figure 48-72 
(From Hare 1960b ) 


FIGURE 48-74 Skeleton of distal part ofleft pelvic limb 
of dog dorsal Mew 

L lateral malleolus (distal end of fibula) Me 5 fifth metatarsal 
bone P 1 P 2 P 3 proximal middle and distal phalanges of 
fifth dipt P 1 P 3 phalanges of first digit S dorsal sesamoid 
Tt talus Tc central tarsal bone T2 T3 T4 second third 
and fourtl tarsal bones T f calcat eus 




1465 


48— CARNIVORE OSTEOLOGY 

with the tibia and fibula The plantar surface 
has three facets for articulation with the cal 
caneus The head is directed a little medxad 
and articulates with the central tarsal bone 
The calcaneus (fibular tarsal) has a long dor 
sal coracoid process or “beak," but the sus- 
tentaculum is short The calcaneal tuber pre- 
sents a sagittal groove The central tarsal bone 
has a concave proximal surface adapted to the 
head of the talus Its distal surface articulates 
with the first, second and third tarsals It 
bears two plantar tubercles The first tarsal is 
flattened and is irregularly quadrangular, its 
proximal surface articulates with the central 
tarsal, and the distal with the first metatarsal 
The second tarsal is the smallest and is wedge 
shaped, it articulates distally with the second 
metatarsal bone The third tarsal is also 
wedge shaped, the base being dorsal, it ar 
ticulates with the third metatarsal distally 
The fourth tarsal is remarkably high, and re 
sembles a quadrangular prism, its proximal 
surface articulates with the calcaneus, its 
distal with the fourth and fifth metatarsal, and 
its medial with the central and third tarsal 
bones A groove for the tendon of the fibulans 
longus crosses its lateral and plantar surface, 
proximal to it are one or two tubercles The 
calcaneal tuber fuses with the body of the 
bone at fourteen or fifteen months 


METATARSAL BONES 

Five metatarsal bones are present The first 
is commonly very small and has the form of a 
blunt cone, somewhat compressed laterally 
It articulates with the first tarsal and furnishes 
insertion to the tibialis cranialis In some cases 
it fuses with the first tarsal, when the first 
digit is well developed its metatarsal may re 
semble the others (except m sue) or be re 
duced in its proximal part to a fibrous band 
The other metatarsals are slightly longer than 
the corresponding metacarpals TTieir proxi 
mal ends are elongated dorsoplantarly and 
have plantar projections, which, in the case of 
the third and fourth, usually have facets for 
articulation with two small, rounded sesamoid 
bones In other respects they resemble the 
metacarpals 


DIGITS 

The first digit is often absent When present, 
its development varies and it contains one or 


FIGUUF 48-77 Right hock joint and distal end of 
tibia and fibula of 1 j ear-old female German Shep- 
herd, plant arodorsa] Mew 

(From Hare lOGQx) 




1466 


CARMVORF 



FIGURE 48-79 Right hock Joint and distal end of tibia and fib- 
ula of CVi-month-old male German Shepherd plantarodoraal 



(From Hare 1960b) 



48 -CARNIVORE OSTEOLOGY 


1467 



Diaphysis (fibula) 

Distal epiphysi * (fibula ) 

Aiticulai surface (lateial gtooie) 
Giotne oflateial malleolus 
Calcaneus 

•Aittculai siajace (medial gtooie) 
Fourth ten sal 
Third taisal 


FIGURE 48-80 Labelled tracing of Figure 48-79 
(From Hare 1960b) 


two phalanges In other cases- especially in 
very large dogs-a sixth digit is present, it 
does not articulate with the metatarsus, but is 
attached by fibrous tissue The phalanges of 


the other digits resemble those of the thoracic 
limb 

Ossification of the metatarsal bones and 
phalanges is complete at five or six months 


SKULL* 


OCCIPITAL BONE 

(Figs 48-83, 84, 85 and 96) 

The occipital bone is similar in position to 
that of the horse The nuchal crest is promi- 
nent and angular, and is directed caudad 
Just ventral to the crest are two rough im- 
prints or tubercles for muscular attachment 
The surface ventral to these is convex from 
side to side and concave dorsoventrally On 
each side, at the junction with the squamous 
part of the temporal bone, is the large mas- 
toid foramen, which opens into the cranial 
cavity and which lies dorsal and rostral to the 
large foramen magnum. The condyles are 
somewhat flattened and are widely separated 
dorsally, at the medial side of each is a short 
condyloid canal, which opens into the tempo 
ral meatus The jugular processes arc very 
short The basilar part is wide and joins the 
tympanic bulla on either side, its ventral sur- 
face is flattened and the tubercles are at the 
junction with the bulla The canal for the liy- 


*ln llip follDwlns description* of the separate bone* art 
Intermediate ivpc-e r., a fox trrrier-l* selected and the 
mtm strtVinc difference* tn the Imthynphilic and doll 
choceplullc breed* will becon*iderrd tn the section on ihe 
ifcullata whole 


poglossal nerve is small and is close to the 
jugular foramen; the latter is bounded rostral- 
ly by the tympanic bulla, caudally and medial- 
ly by the occipital bone The squamous part 
(supraoccipital bone) fuses with the inter- 
parietal before birth, forming the interparietal 
process The bone develops from four centers 
— the squamous part, two condylar parts and a 
basilar part (Miller etal, 1964) 


INTERPARIETAL BONES 

(Fig 48-83) 

The interparietal bone fuses with the supra- 
occipital (which becomes the squamous part 
of the occipital) before birth, forming the 
interparietal process. It bears the high caudal 
part of the external sagittal crest (Fig 48-84), 
and Is wedged between the two parietal bones 
The rostral end is narrower and thinner than 
the caudal Internally it forms the central part 
of the osseous cerebellar tentorium, which is 
thin and curved, and concave ventrally Its 
base concurs with the occipital and parietal 
bones in the formation of the canal for the 
transverse sinus which is continuous ventral- 
ly with the temporal meatuses and dorsally 
w ith the sulcus for the transverse sinus 



14G8 


CARNIVORE 


It hit it n till fit ri*K 



FIGURE 48-81 Skull of doll 
chocephalie dog, dorsal view 


PARIETAL BONES 

(Figs 48-81,83 84 and 96) 

The panetal bone is rhomboid in outline and 
is strongly curved It is extensive and forms 
the greater part of the roof of the cranial cavi 
ty At the junction of the nght and left bones 
there is a prominent external sagittal crest 
which is continued upon the frontal bones 



FIGURE 48-82. Skull of bnehjecphalic dog dor 
»al rirw 


The ventral border articulates with the wing 
of the basisphenoid by its rostral part and with 
the squamous part of the temporal in the re 
mainder of its extent The external surface 
enters into the formation of the temporal fossa 
The internal (cerebral) surface is marked by 
digital impressions and ndges corresponding 
to the cerebral gyri and sulci and by grooves 
for the middle meningeal artery and its 
branches 


FRONTAL BONES 

(Figs 48-81 83 84 and 96) 

The external surface of the frontal bone is 
crossed by the temporal line, which extends 
m a curve from the external sagittal crest to 
the zygomatic process and separates the 
squama from the temporal surface The fron 
tal squama of both sides together form a 
centra! depression and slope \emrad and ros 
trad The zygomatic process is \try short 
(Fig 48-84) so that the supraorbital margin 
is incomplete as in the pig In 60 percent (of 
25) skulls examined by Diesem® the supra 
orbital foramen was present, the opening 


‘Fcnonal communication 



48 -CARNIVORE OSTEOLOGY 


1469 



FIGURE 48-83 Cranial and orbital regions of *kull of dog The zjRomatic arch has been sawn off 

A Occipital bone B interparietal bone C parietal bone- D squamous pan of temporal bone E E temporal and orbital 
parts of frontal bone F wing of presphenoid bone F wing of basisphenoid bone C j erpendicular part of palatine bone 
H pterygoid bone 1 lacrimal I one J maxilla 1 external sagittal tresi 2 nuchal crest 3 occipital condyle 4 jugular 
process 5 M\lomastold forimcn f tytnpinlc bulla 7 external acoustic me Hus 8 anicularsurf ice for condyle of mandi 
ble 9 section ol toot ol rygomitic process of temporal bone 10 alar canal 11 orbital fissure 12 optic canal 13 eth 
moidal foramen 14 caudal palatine foramen 15 sphenopalatine forimcn 16 entrance to lacrimal canal 17 zygomatic 
process 18 Irontal process of zygomatic bone (section) 19 maxillan forimcn 20 last molar tooth 


varying from hardly perceptible to 2 mm in 
diameter (two skulls exhibited a foramen on 
one side only) Rostnlly there is a narrow, 
pointed msal part which fits between the 
nasal bone and the maxilla The orbital and 


temporal surfaces are relatively extensive 
Two ethmoidal foramina are commonly pres 
ent and are formed entirely in the frontal 
bone (McFadyean 1953) The frontal sinus is 
confined to the frontal bone The bone articu 



bone r C ' PUa 1x300 B Parietal bone C squamous part of temporal bone D frontal bone E lacrimal bone F zygomatic 
tr«t cj Perpendicular part of palatine bone H maxilla I incisive bone J nasal bone K mandible 1 external sagittal 
e «enwl^ CCipltal condyle 3 Jugular process A stylomastoid foramen 5 tympanic bulla 6 external acoustic meatus 7 
of zyEDmi^ nl | MK of ,etr >P«ral meatus 8 retroarticular process 9 zygomatic process of temporal bone 1 0 frontal process 
rnenui fr^ C , ne n zygomatic process of frontal bone 12 entrance to lacrimal canal 13 infraorbital foramen 14 
^ssetpri r 04 13 condylar process of mandible 16 coronofd process 17 mandibular notch 18 angular process 19 
nc fossa » 1 Incisor teeth c c canine teeth 



1468 


CARNIVORE 


lllltl /»« * J fill I />• IK t X* 



FIGURE 48-81 Skull of doli- 
chocephalic dog, dorsal view. 


PARIETAL BONES 

(Figs 48-81, 83, 84 and 96) 

The panetal bone is rhomboid m outline and 
Is strongly curved It is extensive and forms 
the greater part of the roof of the cranial cavi- 
ty At the junction of the right and left bones 
there is a prominent external sagittal crest 
which is continued upon the frontal bones 



FIGURE 48-82 Skull of brachy cephalic dog. dor- 
sal view. 


The ventral border articulates with the wing 
of the basisphenoid by its rostral part and with 
the squamous part of the temporal m the re 
mainder of its extent The external surface 
enters into the formation of the temporal fossa 
The internal (cerebral) surface is marked by 
digital impressions and ndges corresponding 
to the cerebral gyn and sulci and by grooves 
for the middle meningeal artery and its 
branches 


FRONTAL BONES 

(Figs 48-81, 83, 84 and 96) 

The external surface of the frontal bone is 
crossed by the temporal line, which extends 
m a curve from the external sagittal crest to 
the zygomatic process and separates the 
squama from the temporal surface The fron- 
tal squama of both sides together form a 
central depression and slope ventrad and ros 
trad The zygomatic process is very short 
(Fig 48-84), so that the supraorbital margin 
is incomplete as in the pig In 60 percent (of 
25) skulls examined by Diesem* the supra 
orbital foramen was present, the opening 

•Penonal communication 



48-CARNIVORE OSTEOLOGY 


1469 



- ,,,.11 Q f doe. The zypomatic arch has been sawn off. 
FIGURE 48-83. Cranial and orbital regions ' temporal bone- E. E\ temporal and orbital 

A, Occipital bone: B, interparietal baswpbenold hone: 9‘ J^JT^IcclpUol'condylcMrjuEV^sf 

E^l M i c S c,?r„ , ir ^t‘or r ^o^ ;rJ^^".n.m°er^^rV G :i»«n^ —'I > 7 - « K o ma «,= 

tfSS« <" *• — rMOmc " “• 

temnoral surfaces are relatively extensi c. 
varying from hardly perceptible to 2 mm t V cthn|oida , foramina are commonly pres- 

diameter (two skulls exhibited a foramen ent an d are formed entirely in the frontal 

one side only). Rostrally there is a narrow, (McFadyean, 1953). The frontal sinus is 

pointed nasal par, which fits between he bone ^ ^ ^ bonc articu- 

nasal bone and the maxilla. The orimm anu 




FIGURE 18 -M. SVntl of do*: 1 * 1 * ***** 

n fonts) fcr»fie. E. UcnnvJ bone. V, nf«*n*tK 
A.Of«trit*l bow. Tl.r-Tirtat U*«. c Vw* J. mut t«w. K. mjmt.tJr , l.fMrrwl MfUta! 

I-**, <- pcfj»f»SKvUf fwiirt p*l*t\r* bn>w . H. ^£tZxt^4U*xnx". a. tTwp»ft* t*HJ. rtirtw) ««*♦«*** ***««»•_•- 


»tr>1.2.«xif4uilcw>tJ*V. 3 iu«uUf rfr-ri*«» 


« tx~» i . rf.miiro,*""'-'-. - »_ . ■ rl . o titHRitvf from, ft inn^vilbitif, |{j, f j i .m m * 

of nr»un «- rrfrnvmcArlar *-**. *•* * ^ £,<«««: r *n»5. 13. Wr«w«*> fot*mn*. T«. 

*< nr"«-‘X *«*♦: it. *•; . .^1 17 . n«eb. t»- ***ul»» rn*'*«, J*>. 

♦S»*vv»<«-rs<; U I, i-<»w C.€\ «*<**»* 



carnivore 


lates with the maxilla, parietal, basisphenoid, 
nasal, lacrimal, palatine and ethmoid bones 
In large breeds a considerable part of the ex 
temal surface of the bone concurs in the 
formation of the temporal fossa. 


TEMPORAL BONES 
(Figs 48-81, 83 and 84) 

The parts of the temporal bone fuse early 
The zygomatic process curves widely lateral 
and rostrad Its rostral part Is beveled ventral 
ly and articulates extensively with the tern 
poral process of the zygomatic The articular 
surface for the condyle of the mandible con 
of a tittnvreree grow*, wVnoVi vs oorAfn 
ued upon the rostral part of the large retro- 
articular process Caudal to the latter is the 
ventral opening of the temporal meatus There 
is no articular tubercle The mastoid portion is 
small but there is a distinct mastoid process 
The external acoustic meatus is wide and very 
short, so that one can see into the tympanurn 
in the dry skull The tympanic bulla is very 
large and is rounded and smooth, its medial 
side is united to the basilar part of the occip- 
ital bone Dorsal to this junction and roofed 
in by the union of the petrous part of the tern 
poral and the basal part of the occipital is the 
petrooccipital canal, this transmits a vein 
from the floor of the cranium to the jugular 
foramen. The latter opens into a narrow de 
pression caudal to the tympanic bulla It 
transmits the ninth, tenth and eleventh era 
nial nerves The carotid canal branches off 
from the petrooccipital canal, passes rostrad, 
lateral to it through the medial part of the 
tympanic bulla, and opens rostrally at the 
carotid foramen, it transmits the internal 
carotid artery The auditory (Eustachian) 
opening is immediately lateral to the carotid 
foramen The muscular and styloid processes 
axe extremely rudimentary The petrous part 
projects into the cranial cavity and forms a 
sharp, prominent petrosal crest The medial 
surface presents a deep cerebellar (floccular) 
fossa dorsal to the internal acoustic meatus 
The rostral surface is also free The rostral 
angle is perforated by a canal for the tngeifli 
nal nene 


SPHENOID BONES 

(Figs 48-83 85 and 96) 

The sphenoid bones form the rostral two 
thirds of the base of the neurocranium be 
tween the basioccipital caudally and the 
ethmoid rostrally There are two bones, the 
rostral presphenoid and the caudal basisphe 
noid 


Bosisphenoid Bone 

The basisphenoid bone is composed of a 
body, a pair of wings and pterygoid processes 
It articulates with the temporal, parietal, 
frontal, occipital and presphenoid 
The cerebral surface of the sella turcica is 
slightly dished, to form the oval hypophyseal 
fossa. The hypophyseal fossa is limited caudal 
!y by the dorsum sellae, which, in adult 
skulls, is flattened and expanded at its free 
end Projecting rostrally on either side of the 
dorsum sellae is a caudal clinoid process 
The wings are larger than the wings of the 
presphenoid and curve laterad and dorsad At 
the base of each wing, near its junction with 
the body, are a senes of foramina The oval 
loramen, media) to the temporomandiWca 
joint, is a large opening which leads directly 
through the cranial wall An indistinct spi- 
nous foramen may be present or may blend 
with the oval foramen The alar canal runs 
through the rostral part of the base of the 
wing The caudal alar foramen is smaller than 
the rostral In its dorsolateral part the rostral 
alar foramen contains a short canal or fis 
sure, the small alar foramen It is penetrated 
on its dorsal surface by the round foramen, 
which leads directly into the cranial cavity 
The rostrodorsal edge of the wing of the basi 
sphenoid bone is marked by a distinct notch, 
the orbital incisure, which together with that 
of the presphenoid forms the orbital fissure 
Penetrating the basisphenoid bone, slightly 
below the external opening of the orbital fis 
sure, is the pterygoid canal, occasionally pres 
ent as an incomplete canal in the floor of the 
orbital fissure, which transmits the pterygoid 
nerve The caudal border of the base of the 
wing presents two notches medially the 
carotid incisure concurs with the temporal 
bone to form the external carotid foramen, 
laterally a notch and rostral groove and its 
counterpart on the temporal bone form the 
short osseous auditory tube 

The thin sagittal pterygoid processes ex 
tend rostroventrally from the body 

Presphenoid Bone 

The presphenoid bone is composed of a body 
and a pair of wings It articulates with the 
basisphenoid, frontal, ethmoid and vomer 

Caudally it completes the rostral part of the 
floor of the middle cranial fossa, where it is 
marked by a shallow groove, the chiasmatic 
sulcus, in which lies the optic chiasma From 
here the sulcus is continued rostrolaterally, 
penetrating the bone 

The wings, which leave each side of the 
body, are smaller than those of the basisphe 
noid At the junction of the wings and the 
body, the presphenoid is hollow and divided 



48-CARNIVORE OSTEOLOGY 


1471 


Foramen Occipital 

Canal for hypoglossal nerve magnum condyle 


Jugular foramen 
Stylo mastoid fo » amen 



Jugular piocess 
Tympanic bulla 
Temporal meatus 


Premolar teeth 


Canine tooth 


Frontal process of 
zygomatic bone 

fl-JA 

1 Palatine process of maxilla 

m 

t\\ \*L 


Incisor teeth 

FIGURE 48-85. Skull of dog; central »iew, without mandible. 


A, Basilar part of occipital bone; B, body of basisphenold bone, C. vomer, D, D', perpendicular and horizontal parts of 
palatine bone , E, pterygoid bone, 1, auditory opening; 2, external carotid foramen, 3, oval foramen, 4, 5, caudal and rostral 
openings of alar canal, 6, orbital fissure, 7, retroarticular process, 8, articular groove of temporal bone, 9, zygomatic 
process; 10, nasopharyngeal meatus; 11, major palatine foramen, 12, palatine groove, 13, palatine fissure, 14, lnterin- 
clslve canal There is a supernumerary incisor on the right side In this specimen 


by a longitudinal septum to form the sphe- 
noidal sinuses, filled by the ventrocaudal parts 
of the ethmoturbinates. In the frontosphe- 
noidal suture is located the ethmoidal foramen, 
which may be confluent with the ethmoid 
foramen of the frontal bone. 

Internally and rostrally the body is elevated 
and completes the floor of the rostral cranial 
fossa. The paired optic canals are bridged over 
dorsally by the jugum, the fusion of the right 
nnd left wings, ventral to which they are con- 
fluent. Caudolaterally, at the junction of the 
wing with the body, the presphenoid is marked 
by a shallow notch which concurs with that of 
the baslsphcnoid in the formation of the 
orbital fissure. Dorsally a crest overhangs the 


fissure. Extending in a caudal direction from 
the crest, slightly lateral to the middle, are 
the blunt rostral clinoid processes. 

ETHMOID BONE 

(Fig. 48-9G) 

The ethmoid bone is highly developed. The 
cribriform plate is extensive, and the ethmoidal 
(olfactory) fossae are very deep. The crista 
gnlli (ethmoidal crest) is little developed, and 
often is incomplete. The perpendicular plate 
is long. The labj-rinths (lateral masses) arc 
greatly developed and project into the frontal 
sinus. There arc four large endoturbinate* and 
six ectoturbf nates. The orbital (lateral) plate 



CXRNIVORE 


1472 

is extensive and forms the medial wall of the 
maxillary sinus Its ventral border joins the 
palatine process of the maxilla and the hon 
zontal part of the palatine bone A shelfhke 
plate extends medially from its ventral part 
and concurs with the similarly incurved part 
of the palatine bone in forming the basal plate 
which divides the olfactory fundus of the 
nasal cavity from the nasopharyngeal meatus 
The dorsal nasal concha is in its rostral part, 
a simple plate attached by one edge to the 
ethmoidal crest of the nasal bone, it curves 
ventromedially and its free border is thick 
ened and everted The caudal part Is wider 
and resembles the ethmoturbmates, with 
which it is connected 


VENTRAt NASAL 
CONCHA! BONE 

The ventral nasal concha is short and very 
complex It is attached to the conchal crest of 
the nasal surface of the maxilla by a basal 
plate which divides into two secondary lamel 
lae The latter detach numerous tertiary lamel 
lae, which are coiled and have thick free 
edges 


MAXIUAE 

(Figs 48-81, 84 and 85) 

The maxilla is short, but very high caudally 
The facial crest is absent The infraorbital 
foramen is over the alveolus for the third pre 
molar The infraorbital canal is short The 
frontal process fits into a deep notch between 
the nasal and orbital parts of the frontal bone, 
and the middle part of the caudal border lies 
along the orbital margin There are more or 
less pronounced ridges, juga alveolaria, over 
the canine and molar teeth The zygomatic 
process is short and thin, it is completely 
overlapped laterally by the zygomatic bone 
and is perforated by a number of alveolar 
foramina A maxillarj tuber is not present in 
the adult, but there is a pointed projection 
caudal to the last alveolus The nasal surface 
bears a short conchal crest on its rostral part, 
caudal to which it is deeply concave and forms 
the lateral wall of the small maxillary recess 
The palatine process is short, wide caudally, 
and moderately arched from side to side The 
major palatine foramen is situated at or close 
to the transverse palatine suture and about 
midway between the median palatine suture 
and the alveolar border The palatine groove 
is distinct The large alveolus for the canine 
tooth is completed by the incisive bone The 
small alveolus for the first premolar ts sepa 
rated from the preceding one by a small inter 
vab The next two consist of rostral and 
caudal parts for the roots of the teeth The 


fourth and fifth are much larger and are 
divided into three parts The last Is small and 
consists of three divisions 


INCISIVE BONES 

(Figs 48-81, 84, 85 and 96) 

The body of the incisive bone is compressed 
dorsoventraliy, and contains three alveoli for 
the incisor teeth, which increase in size from 
first to third, it also completes the medial wall 
of the large alveolus for the canine tooth The 
interincisivc canal is very small except in 
large skulls The interalveolar border Is wide 
and very short The nasal process Is wide at its 
origin and tapers to a sharp point caudally, the 
rostral part curves dorsally, caudally and 
slightly medially, and forms the lateral mar- 
gin of the osseous nasal aperture, the caudal 
part extends caudally for a long distance be 
tween the nasal bone and the maxilla The 
palatine process turns dorsad and laterad, 
forming with its fellow of the opposite side a 
wide groove for the septal cartilage, the caudal 
end is pointed and fits into a notch between 
the palatine processes of the maxillae, and 
supports the end of the vomer The palatine 
fissure is short but wide 


PALATINE BONES 

(Figs 48-83 84, 85 and 96) 

The horizontal plate of the palatine bone is 
extensive forming about one third of the hard 
palate It presents a variable number of minor 
(accessory) palatine foramina. There is usual 
ly a pointed caudal nasal spine at the end of 
the median suture The major palatine canal 
is sometimes formed entirely in this bom; The 
perpendicular plate is even more extensive 
Its lateral surface is chiefly free and forms 
most of the medial wall of the large pterygo- 
palatine fossa The maxillary foramen is situ 
ated in a deep recess between this bonearid the 
zygomatic process of the maxilla Just dorsal 
to it there is commonly another foramen 
which opens into the nasal cavity The major 
palatine and sphenopalatine foramina arc situ 
ated farther caudad and a little more ventral 
the former is ventral to the latter A horizon’ 
tal plate extends from the nasal surface 
meets that of the opposite bone, and completes 
the basal plate spoken of in the description of 
the ethmoid bone There is no palatine sinus 


PTERYGOID BONES 
(Figs 48-83, 85 and 96) 


J2 tery ? 0,d k° nes are very wide and 
short They form a considerable part of the 
lateral boundaries of the choanae (caudal 



48- CARNIVORE OSTEOLOGY 


1473 


nares). The ventral and caudal borders are 
free, and at their angle of junction there is a 
variable hamulus. 

NASAL BONES 

(Figs. 48-81 and 96) 

The nasal bones are (in most breeds) long 
and wider ros trail y than caudally. The exter- 
nal (facial) surface is variably concave in its 
length and is inclined toward the median su- 
ture so as to form a central groove. The medial 
borders turn ventrad and form an internal 
ethmoid crest, which becomes very prominent 
caudally. The caudal parts fit into a notch 
formed by the frontal bones. The rostral ends 
form an almost semicircular nasal notch. 


LACRIMAL BONES 

(Figs. 48-81, 83 and 84) 

. The lacrimal bone is very small. The facial 
surface extends very little or not at all beyond 
the orbital margin. The orbital surface is 
small and triangular, and presents the en- 
trance to the lacrimal canal. The bone articu- 
lates with the palatine. 


ZYGOMATIC BONES 

(Figs. 48-81, 84 and 85) 

The large temporal process constitutes the 
bulk of the zygomatic bone. It is very long and 
is strongly curved. The dorsal border is convex, 
is free rostrally, where it forms part of the 
orbital margin, and is beveled caudally for 
articulation with the similar process of the 
temporal bone. Between these it bears an 
eminence, the frontal process, to which the 
orbital ligament is attached. The body of the 
bone may be considered to consist of a ^lacri- 
mal process directed dorsally and fitting be- 
tween the lacrimal and maxilla, and a ^maxil- 
lary process directed ventrally. The facial 
surface is convex. 


VOMER 

(Fig. 48-96) 

The vomer is not in contact with the caudal 
part of the floor of the nasal cavity, and does 
not divide the choanae. The caudal end is 
narrow and deeply notched. Near the choanae 
the two plates curve laterad, and join the pala- 
tine bones and assist in forming the basal 
plate. 

MANDIBLE 

(Figs. 48-84 and 86) 

The two halves of the mandible do not fuse 
completely even in old age, so that there is a 
permanent symphysis. The body presents six 
alveoli for the incisor teeth and two for the 
canines. The incisor alveoli increase in size 
from first to third. The canine alveoli extend 
deeply ventrad and caudad. The divergence is 
less than m the pig. The ventral border of the 
molar part is convex in its length, and is thick 
and rounded. The alveolar border is slightly 
concave in its length, and is a little everted, 
especially in its middle; it presents seven al- 
veoli for the lower cheek teeth, which re- 
semble those of the upper jaw except that the 
fourth and sixth are much smaller and the 
fifth is like the fourth of the upper series. The 
interalveolar space is very short or may even 
be absent. There are two or three mental fora- 
mina on either side. The ramus is relatively 
small. Its lateral surface presents a deep mas- 
seteric fossa, which encroaches on the coro- 
noid process and is limited by ridges rostrally 
and ventrally. The medial surface is convex, 
and is marked by the usual mandibular fora- 
men. At about the same level as the latter is 
the rough angle which projects caudally from 
the caudal border. The condylar process is 
placed very low— not much higher than the 
apex of the canine tooth when the bone is 
resting on a flat surface. It is long transversely, 
and the medial part of the articular surface is 
much the wider and extends over the caudal 



FIGURE Right half of mandible of dor; tnrdii) view. 



1472 


CUtMVORE 


is extensive and forms the medial wall of the 
maxillary sinus Its ventral border joins the 
palatine process of the maxilla and the hon 
zontal part of the palatine bone A shelflike 
plate extends medially from its ventral part 
and concurs with the similarly incurved part 
of the palatine bane in forming the basal plate 
which divides the olfactory fundus of the 
nasal cavity from the nasopharyngeal meatus 
The dorsal nasal concha is, in its rostral part, 
a simple plate, attached by one edge to the 
ethmoidal crest of the nasal bone, it curves 
ventromedially, and its free border is thick 
ened and everted The caudal part is wider 
and resembles the ethmoturbinates, with 
which It is connected 

VENTRAL NASAL 
CONCHAl BONE 

The ventral nasal concha is short and very 
complex It is attached to the conchal crest of 
the nasal surface of the maxilla by a basal 
plate which divides into two secondary Iamel 
lae The latterdetachnumerous tertiary lamel 
lae, which are coiled and have thick free 
edges 


MAXILLAE 

(Figs 48-81, 84 and 85) 

The maxilla is short, but very high caudally 
The facial crest is absent The infraorbital 
foramen is over the alveolus for the third pre 
molar The infraorbital canal is short The 
frontal process fits into a deep notch between 
the nasal and orbital parts of the frontal bone, 
and the middle part of the caudal border lies 
along the orbital margin There arc more or 
less pronounced ndges, juga aheolaria, over 
the canine and molar teeth The zygomatic 
process is short and thin, it is completely 
overlapped laterally by the zygomatic bone 
and is perforated by a number of alveolar 
foramina A maxillary tuber is not present m 
the adult, but there is a pointed projection 
caudal to the last alveolus The nasal surface 
bears a short conchal crest on its rostral part, 
caudal to which it is deeply concave and forms 
the lateral wall of the small maxillary recess 
The palatine process is short wide caudally, 
and moderately arched from side to side The 
major palatine foramen is situated at or close 
to the transverse palatine suture and about 
midway between the median palatine suture 
and the alveolar border The palatine groove 
is distinct The large alveolus for the canine 
tooth is completed by the incisive bone The 
small alveolus for the first premolar is sepa 
rated from the preceding one by a small inter 
vaJL The next two consist of rostral and 
caudal parts for the roots of the teeth. The 


fourth and fifth are much larger and are 
divided into three parts The last is small and 
consists of three divisions 


INCISIVE BONES 

(Figs 48-81, 84, 85 and 96) 

The body of the incisive bone is compressed 
dorsoventrally, and contains three alveoli for 
the incisor teeth, which increase in size from 
first to third, ft also completes the medial wall 
of the large alveolus for the canine tooth The 
mterincisive canal is very small except in 
large skulls The interalveolar border is wide 
and very short The nasal process is wide at its 
origin and tapers to a sharp point caudally, the 
rostral part curves dorsally, caudally and 
slightly medially, and forms the lateral mar 
gin of the osseous nasal aperture, the caudal 
part extends caudally for a long distance be 
tween the nasal bone and the maxilla The 
palatine process turns dorsad and laterad, 
forming with its fellow of the opposite side a 
wide groove for the septal cartilage, the cau dal 
end is pointed and fits into a notch between 
the palatine processes of the maxillae, and 
supports the end of the vomer The palatine 
fissure is short but wide 


PALATINE BONES 
(Figs 48-83 84, 85 and 96) 

The horizontal plate of the palatine bone is 
extensive forming about one third of the hard 
palate It presents a variable number of minor 
(accessory) palatine foramina There is usual 
ly a pointed caudal nasal spine at the end of 
the median suture The major palatine canal 
is sometimes formed entirely in this bone The 
perpendicular plate is even more extensive 
Its lateral surface is chiefly free and forms 
most of the medial wall of the large pterygo* 
palatine fossa The maxillary foramen is situ 
ated m a deep recess between this boneand the 
zygomatic process of the maxilla Just dorsal 
to n there is commonly another foramen 
which opens into the nasal cavity The major 
palatine and sphenopalatine foramina are situ 
ated farther caudad and a little more ventral, 
Che former is ventral to the latter A horizon 
tal plate extends from the nasal surface, 
meets that of the opposite bone, and completes 
the basal plate spoken of in the description of 
the ethmoid bone There is no palatine sinus 


PTERYGOID BONES 

(Figs 48-83, 85 and 96) 

The pterygoid bones are very wide and 
short They form a considerable part of the 
lateral boundaries of the choanae (caudal 



48 — CARNIVORE OSTEOLOGY 


1475 



FIGURE 48-88 Skull of female German Shepherd; left lateral view 
(From Hare 1958) 



CARNIVORE 


1474 

surface Its long axis is a little oblique, the 
me dial end being inclined somewhat ventrad 
and rostrad The coronoid process (Fig 48-81) 
is very extensive and is bent slightly laterad 
andcaudad 


HYOID BONE 

(Fig 48-87) 

The basihjoid is a slightly curved trans 
verse rod, it is compressed from rostral to 
caudal, and bears no lingual process The 
thyrohjoids are permanently attached to the 
basihyoid by cartilage, they diverge widely, 
curve medially, and are compressed laterally 
The ceratohjoids (small cornua) are short, 
prismatic and strong. The epthyoids (middle 
cornua) are commonly a little longer than the 
stylohyoids, they are compressed laterally, 
and are shghtly enlarged at the ends, which 
are joined by cartilage to the adjacent cornua. 
The stylohy oids are bent laterad and are some 
what twisted 


SKULL AS A WHOLE 


The different breeds of dogs display great 
variations m the form and size of the skull 
Those which have a long, narrow skull (e g , 
greyhound, collie) are designated dolichoce- 
phalic (Fig 48-81) Other dogs (e g , bulldog, 
small spaniels, pug) have very broad, short 
skulls and are termed brachyeephalic (Fig 
48-82) Intermediate forms (e g , fox terrier, 
dachshund) are mesati cephalic. 

The length of the skull is usually measured 
from the nuchal crest to the rostral end of the 
intenncisive suture, and the breadth between 
the summits of the zygomaUc arches The 
cephalic index is the relation of the breadth to 
the length, assuming the latter equals 100, 



1 Tjmpaaohjmi 2, stylohyoid 3 epihyoid 4 crrato- 
hyoid 5 thyrohyoid 6 cartiiiKe of 5 7 hajlhyold. 


the formula is °° —cephalic index. 

The index of extreme dolichocephalic breeds 
is about 50, as m the greyhound, and that of 
the brachyeephalic specimens may be as high 
as 90, as m the pug and some toy temers 
Among the mesadeephahe types are the fox 
temer, with an index of about 70, and the 
white Pomeranian, with an index of about 72 
to 75 The craniofacial index is the relation 
ship of the distance between the nuchal crest 
and the frontonasal suture to that between tbe 
latter and the nasoincisive notch It vanes 
from 10 3 in extreme brachyeephalic breeds 
to 10 7 in extreme dolichocephalic subjects 
The frontal surface shows the wide outward 
curve of the zygomatic arches and the great 
extent of the temporal fossae. The latter are 
separated by the external sagittal crest, which 
in the larger breeds is very strong and pn>mi 
nent, and is continued by the diverging tern 
poral lines to the zygomatic processes The 
frontal and nasal regions are centrally de- 
pressed, and are more or less concave in pro- 
file The nasal region is narrow, and is term! 
nated rostrally by a nasoincisive notch. In the 
extreme brachyeephalic breeds the differ- 
ences are very striking (Fig 48-82) The ora 
mum is strongly convex m both directions, 
and is considerably longer than the face The 
external sagittal crest is more or less effaced 
caudally, and is formed by the interparietal 
only The temporal lines are separated by an 
interval caudally, and diverge to the zygo- 
matic processes, so that the temporal fossae 
are widely separated. The frontal region is 
wide, strongly convex, and has a shallow cen 
tral depression The nasal region is very short, 
relatively wide, and centrally depressed. In 
profile there is a marked depression at the 
frontonasal junction, producing what is 
termed by fanciers the "stop” of the face 
On the lateral surface the great extent of 
the temporal fossa is seen. The orbit com- 
municates freely with the fossa, the caudal 
part of the orbital margin being absent m the 
dry skull The axis of the orbital cavity forms 
a much smaller angle with the median plane 
than in the horse and ox. A distinct crest, the 
ventral orbital crest, marks the limit between 
the orbital cavity and the extensive pterygo- 
palatine fossa The preorbital region is some 
what triangular, concate in its length, and 
convex dorsoventrally, the infraorbital fora 
men on its * entral part is dorsal to the third 
cheek tooth. In extreme brachyeephalic breeds 
the orbit is relatively very large and the pre 
orbital region extremely short but high. In the 
bulldog the lower jaw protrudes beyond the 
upper— a condition known as prognathism 
The opposite condition, brachygnathism. is 
seen in the dachshund. 



48-CARNIVORE OSTEOLOGY 


1477 



FIGURE 48-90 Skull of female English Bulldog, lateral view 
(From Hare 1958 ) 


Striking features on the basal surface of the 
cranium (Fig 48-85) are the width and flat 
ness of the basilar part of the occipital bone, 
the small size of the jugular processes, the 
large size and rounded shape of the tympanic 
bulla, and the grooved form of the articular 
surfaces for the mandible The choanae are 
long and narrow, and are not divided by the 
vomer The hard palate is usually about half 
the length of the skull It is commonly marked 
by a median crest or rough line, and on each 
side are the major and minor palatine fora 
mina and the palatine grooves The width is 
greatest between the fourth pair of cheek 
teeth, and here there is in most skulls a pro 
nounccd depression on cither side The length 
width, and contour vary greatly in different 
breeds 

The angle of divergence of the mandible 
vanes from 25 to 30 degrees, it is smallest In 
the greyhound largest in extreme bmchy- 
ceph ilic types, e g , bulldog, pug 

The nuchal surface is somcwlnt triangular, 
with the bast ventral The summit is formed 
by the nuchal crest, which projects very 
stronglv caud illy in the large breeds Ventral 
to it there are two very distinct rough im 
prints for muscular attachment In some 


skulls there is a thin, median occipital crest, 
in others a rounded elevation Laterally are 
the temporal crests and the mastoid processes. 
The mastoid foramen is at the j unction of the 
occipital and temporal bones, dorsal to the 
root of the jugular process, it opens directly 
into the cranial cavity The foramen magnum 
vanes greatly in form, most often the trans 
verse diameter is the greatest, but in some 
skulls it is equaled or exceeded by the vertical 
diameter 

The cranial cavity (Fig 48-96) corresponds 
in form and size with the cranium, especially 
in those breeds in which the various crests 
are more or less effaced and the frontal sinuses 
are small The basicranial axis is almost paral- 
lel with the palate, and the floor is flattened 
The rostral cranial fossa is narrow, and is only 
slightly higher than the middle one The eth- 
moidal fossae are very deep, and the crest is 
little developed The hypophyseal fossa is 
vanable in depth and the dors Um scllae is 
relatively high and bears clmoid processes 
lateralis The cerebral and cerebellar compart- 
ments are well marked off Lit era fly by the 
petrosal crests and dorsally by the osseous 
tentorium The base of the latter is traversed 
by a canal, which connects tht; two temporal 




Co>OMO«d procrs 


1476 


CARNIVORE 



( 8S61 'a«H wmj) 


48 -CARNIVORE OSTEOLOGY 


1479 


FIGURE 48-92. Skull of female German 
Shepherd; ventrodorsal view. 

(From Hare, 1958 ) 



meatuses. The rostral angle of the petrous part 
of the temporal bone is perforated by a canal 
for the trigeminal nerve. 


Nasal Cavity 

The nasal cavity (Fig- 48-96) conforms to 
the shape of the face. Its rostral aperture is 
large and nearly circular in most dogs. The 
complex ventral nasal conchae occupy the 
rostral part of the cavity to a large extent, ex- 
cept near the aperture. Caudal to the ventral 
nasal concha is the large opening of the max- 
illary recess. Caudal to this the cavity is di- 
vided by the. basal plate into a large dorsal ol- 
factory region or nasal fundus and a lower 
nasopharyngeal meatu^. The fundus is occu- 
pied largely by the ethmoturbinates. The 
choanac axe undivided and are, in general. 


long and narrow, but vary with the shape of 
the skull. 


Paranasal Sinuses 

The frontal sinus is of considerable size in 
the large breeds, but is confined to the frontal 
bone. It is usually divided into a small medial 
and a much larger lateral sinus, each of which 
opens into the dorsal ethmoidal meatus. The 
sinus is very small in extreme brachycephalic 
types. 

The maxillary recess is small, and is in such 
free communication with the nasal cavity as 
to make it rather a recess than a true sinus. It 
is bounded medially by the orbital plate of the 
ethmoid, and its lateral wall is crossed oblique- 
ly by the nasolacrimal canal. The roots of the 
molar teeth do not project into it 

( Text continued on page 1483.) 


Coronoid 


1478 


CARNIVORE 



FIGURE 48-91. Labelled (racing of Figure 48-90. 
(From Hare 195a) 




48 -CARNIVORE OSTEOLOGY 


1479 


FIGURE 48-92. Skull or female German 
Shepherd; ventrodorsal view. 

(From Hare, 195B ) 



meatuses. The rostral angle of the petrous part 
of the temporal bone is perforated by a canal 
for the trigeminal nerve. 


Nasal Cavity 

The nasal cavity (Fig 48-96) conforms to 
the shape of the face. Its rostral aperture is 
large and nearly circular in most dogs. The 
complex ventral nasal conchae occupy the 
rostral part of the cavity to a large extent, ex- 
cept near the aperture. Caudal to the ventral 
nasal concha is the large opening of the max- 
illary recess. Caudal to this the cavity is di- 
vided by the, basal plate into a large dorsal ol- 
factory region or nasal fundus and a lower 
nasopharyngeal meatu^, The fundus is occu- 
pied largely by the cthmoturbinates. The 
choanne are undivided and are, in general. 


long and narrow, but vary with the shape of 
the skull. 


Paranasal Sinuses 

The frontal sinus is of considerable size in 
the large breeds, but is confined to the frontal 
bone. It is usually divided into a small medial 
and a much larger lateral sinus, each of which 
opens into the dorsal ethmoidal meatus. The 
sinus is very small in extreme brachycephalic 
types. 

The maxillary recess is small, and is in such 
free communication with the nasal cavity as 
to make it rather a recess than a true sinus. It 
is bounded medially by the orbital plate of the 
ethmoid, and its lateral wall is crossed oblique- 
ly by the nasolacrimal canal. The roots of the 
molar teeth do not project into it. 

(Text continued on page 1483 !) 



48— CARNIVORE OSTEOLOGY 


1481 



FIGURE 4&-96. Sagittal section of skull of dog. without mandible. 

A, A', Basilar and squamous parts of occipital bone. B. B , presphenoid and baiiiphenoid bones. C, C', perpendicular and 
cribriform plates of ethmoid bone. D. parietal bone, E, frontal bone. F. pterygoid bone G, G .vertical and horizontal parts 
of palatine hone. I! vomer. 1, incisive bone, J. nasal bone. K. dorsal natal concha, L. tentral natal concha, I, II, III, ros- 
tral, caudal and middle fossae of cranium. 1. occipital condyle, 2. opening of condyloid canal, 3, canal for tntertransvetv 
sinus of dura mater. 4. Internal occipital protuberance. 5. Internal opening of temporal meatus. 6. mastoid foramen. 7. 
cerebellar fossa 8. Internal acoustic meatus 9. canal for trigeminal nerve, 10. Internal carotid foramen, 1 1, 12, openings 
Into petroocdpital canal. 13 canal for hypoglossal n., 14 petrosal crest, 15. dorsum sellae. 16, hypophyseal fossa. 17. optic 
canal. 18, ethmoid foramen, 19. nasopharyngeal meatus, 20, 21. 22. dorsal, middle and ventral nasal meatuses. 23, Incisor 
teeth, 24. canine tooth. 25 premolarteeth, 26, molar teeth, 27. septum between fitmul sinuses. 



48-CARNIVORE OSTEOLOGY 


1483 


PART II 

It is felt that, at this time, an Atlas type 
presentation of the feline bone structure will 
be of real assistance to the student Accord- 


FE1INE 

ingly, Figures 48-97 through 141 present the 
complete bone structure of the cat. 

(Text continued on page 1503.) 



1, Zygomatic process, 2, orbit, 3, zygomatic arch. 4, maxilla, 5, external acoustic meatus, 6, tympanic bulla, 7, tem- 
poromandibular articulation, 8. angular process, 9, hyoid bone, 10, mandible, 11, mental foramen, 12, external sagittal 
crest, 13, atlas, 14 axis, 15,manubnum, 16, sternum, 17, xiphoid process, 18, costal arch, 19, costal cartilage, 20, crest of 
ilium, 21, ilium, 22, sacrum, 23, pubis, 24, obturator foramen, 25, ischium, 26, scapula 27, spine, 28, clavicle, 29, 
humerus, 30, supracondylar foramen, 31, radius, 32, ulna, 33, carpus, 34, metacarpus, 35, phalanges, 36, thiri digit. 37, 
first digit, 38, head of femur; 39, greater trochanter, 40, tibial tuberosity, 41, cranial margin of tibia, 42, tibia, 43, fibula, 
44, tarsus. 45, metatarsus, 46, fifth digit, 47. femur, 48, popliteal sesamoid bone, 49, patella, 50, plantar sesamoid, 51, 
second digit. III, third cervical vertebra, V, fifth lumbar vertebra, VI. sixth thoracic vertebra, X, tenth caudal vertebra, 
XIII. thirteenth rib (From Sis, 1965 ) 






1484 


CARNIVORE 




FIG UR F 4S-106 L*ft literal radiocraph of tail of adult rat. 
(rrem Si* and Grttr 190% > 





FIGURE 4&-110. Right scapula of cat 

Lateral aspect 1. Caudal angle, 2. cranial angle, 3, supraspinous fossa, 4 infraspinous fossa, 5, spine, 6, acromion 
(processus hamalus), 7, supraglenoid tubercle, 8 acromion (processus suprahamatus) Craniolateral aspect 1, Caudal 
angle 2 spine, 3, acromion (processus suprahamatus) 4 acromion (processus hamatus ) 5, glenoid cavity, 6, coracoid 
process, Medial aspect 1 supraglenoid tubercle, 2, subscapular fossa 3 i utrient foramina. (From Sis 1965 ) 



FIGURE 48-111. Clavicle of cat. 
(From Sis 1965) 




1488 


CARNIVORE 



FIGURE 48-107. Labelled tracing 
of P’igure 48-106. 

(From SI* and Cetty. 19C8 ) 


FIGURE 48-108. Mediolateral radio- 
graph of left thoracic limb of adult eat 


(From SI* and Getty. 19G8 ) 


FIGURE 48-109. Labelled trac- 
ing of Figure 48-108 

(From SI* and Getty, 1968 ) 


Carpet pint j 

Aec essory e<m>d 



FIGURE 48-116. Labelled tracing of Figure 48- 
115. 

Phalanx 1, 2, 3, proximal, middle and distal phalanges 
(From Sis. 1965 ) 


tO x}- 




1490 


CARMVORF 


1 2 1 



FIGURE 48-113 Right radius and ulna of cat medial 
caudal aspect. 

] Trochlear notch of ulna 2 med al coronoid process 3 body 
of radius 4 body of ulna 5 anconeal process C olecranon 7 
styloid process of radius 8 styloid process of ulna. (From S s 
1965) 


FIGURE 48-112 Humerus of cat right 
humerus caudal aspect (left) and left hu 
merus cranial aspect (right) 

1 Greater tubercle 2 lesser tubercle 3 head 
4 supracondylar foramen 5 supratrochlear 
foramen 6 medal epicondyle 7 crcit of 
greater tubercle 8 lateral epicondyle 0 distal 
extremity (From Sis 1065) 




48 —CARNIVORE OSTEOLOGY 


1493 



1 2 3 4 5 6 7 


FIGURE 48-120 Left os coxae of cat, ventrolateral aspect 

1 Ventral caudal iliac spine 2 body of ilium 3 iliopubic eminence 4 pubis 5 acetabular fossa 6 obturator foramen 
7 ischium 8 ischlatic tuberosity 9 ischlatic spine 10 greater ischlatic notch (From Sis 1965 ) 



FIGURE 48-121 Site for epidural Injection In the eat. 

1 , Lumbosacral space 2 sacrum 3 seventh lumbar vertebra. (From Sis. 19CS.) 




1492 


CARNIVORE 



FIGURE 48-117 Mann* of cal* 
(From Si» 19C5) 



FIGURE 48-118 Fused ossa coxarum of cat central aspect. 

J Iliac creit 2 lljac lurface 3 auricular surface 4 body of ilium 5 pubic symphysis C ischlatlc symphysis 7 IschU 
tic tuberosity 8 ischlatlc arch 9 obturator foramen 10 acetabular fossa. (From Sis. 1005 ) 



FIGURE 48-119 PeWta of 
cal, dorsal aspect. 

1 Ischlatlc tuberosity 2 lesser 
ischlatlc notch 3 greater Ischia 
tic notch 4 wing of Ilium 5 era 
nial ventral iliac spine 6 dorsal 
sacral foramina 7 sacroiliac sr 
liculation. (From Sis 1965) 



48— CARNIVORE OSTEOLOGY 


1495 



FIGURE 48-125. Mediolateral radlo- 
*r»ph of left pelvic limb of adult cat- 

CFrom Sti and Getty. 1968 .) 


1494 


CARNIVORE 



FIGURE 4 8 — 122 Ventrodoreal radiography of 
pet vis and cranioeaudat view of stifle joint of adult 


(From Si* and Cetty, I9CB ) 


FIGURE 48-123 Labelled tracing or 
Figure 48-122. 

(From SI* and Getty, 1968 ) 



48— CARNIVORE OSTEOLOGY 


1495 


Greater trochanter - 


Ftrtella 

Sesamoid bones of gastrocntmhn- 

Tlbia 

Fibula 


Hock joint 
-Lett tarsus 


FIGURE 48-124. Labelled tracing of 
Figure 48-125. 

(From Sis and Getty. 1968 ) 


Proximal phalanx- 
Mlddle phalanx-jg 
Distal phalanx*' 


FIGURE 48—125. Mediolateral radio- 
graph of left pelvic limb of adult eat. 

(From Sis and Getty, 1968 ) 



il 



1496 


CARNIVORE 


1 2 3 



FIGURE 48-127. Right femur and patella of eat; caudal 
view. 

1, Fovea of head, 2. trochanteric fossa, 3 greater trochanter; 4, 
nutrient foramen, 5, body, 6. base of patella 7. medial condyle. 
8, intercondylar fossa, 9, lateral condyle, 10, apex of patella. 
(From Sis, 1965) 


FIGURE 48-126. Right femur and patell* of 
eat; cranial view 


1, Greater trochanter, 2. neck, 3, head, 4, bc“T. 5, 
lateral eplcondyle. C. trochlea, 7, medial epieondT ,e . 8 * 
apex of patella. (F rom Sis, 1 965 ) 


7 8 9 to 



48 -CARNIVORE OSTEOLOGY 


1497 


FIGURE 48-128. Left tibia and fibula of cat; cra- 
nial aspect. 

1, Medial condyle, 2 lateral condyle, 3, head of fibula, 4, 
tiblal tuberosity, 5, cranial margin of tibia. 6, Interosseous 
space of leg, 7, tibia, 8, fibula, 9, medial malleolus 10 lat 
eral malleolus (From Sis, 1965 ) 


1 

2 



3 


4 


g FIGURE 48-129. Left tibia and fibula of Cat; lateral aspect. 

1, Head of fibula 2 fibula 3, interosseous space of leg 4 interns 
seous border, 5 Ubla G lateral malleolus (From Sis 1965 ) 




1498 


CARNIVORE 



FIGURE 48-131 Labelled tracing of Figure 48- 
130 

Phalanx 1 2 3 proximal middle and dUtal phalange* 
(From Sit 1965) 



FIGURE 48-130 Plsntarodorsa! radiograph of 
tarsal joint and digits of adult rat 

(From Si* 1065 ) 



FIGURE 48-132 Pesofeat 
(From Si* 1965) 



48 -CARNIVORE OSTEOLOGY 


1499 


FIGURE 48-133. Skull of cat; dorsal 
view. 

1, External nares, 2, nasal bone, 3, open- 
ing into lacrimal cabal, 4, maxilla, 5, zygo- 
matic process of frontal bone, 6, frontal 
bone, 7, mastoid process of temporal bone, 
8, Incisive bone, 9, maxilla, 10, lacrimal 
bone, 11, zygomatic bone, 12, frontal 
process of zygomauc bone, 13, zygomatic 
process of temporal bone, 14, coronal su 
ture, 15, sagittal suture, 16, parietal bone, 
17, nuchal crest (From Sis, 1965 ) 


I 2 




FIGURE 48-134. Skull of cal, sen- 
tral a jew. 

1, Incisive bone 2 Incisors, 3, palatine 
fissure 4. canine tooth, 5, premolars, G. 
molar, 7. frontal bone, B, zygomatic 
process of frontal bone, 9, zygomatic 
arch, 10, oval foramen. 11, external 
acoustic meatus, 12 jugular foramen, 
13, hypoglossal foramen 14, maxilla, 15, 
major palatine foramen 10 minor pala 
tine foramen, 17. palatine bone. IB, 
choanac, 19. presphenoid bone 20 man 
dibular fossa, 21, basisphenoid bone, 22. 
tympanic bulla 23. occipital condyle. 24 
foramen magnum 25 external occipital 
protuberance. 26 . occipital bone (from 
Sis. 1965) 






1500 


CMINWORF 


9 10 11 



FIGURE 48-135 Skull of eat lateral view 


1 Parietal bone 1 occipital bone 3 squamous pan of temporal bone 4 manubrium of malleus 5 external acoustic 
meatus 6 tympanic bulla 7 retroarticular process 8 hamulus of pterygoid bone 9 frontal bone JO fused zygomatic 
process of frontal bone and frontal process of zygomatic bone 11 orbit 12 nasal bone 13 incisive bone 14 maxilla 15 
zygomatic bone 16 canine tooth 17 third premolar 18 molar (From Sis 1965) 



FIGURE 48-136 Left lateral radiograph of head 
of adult eat. 


(From Sis and Getty 1968) 



48— CARNIVORE OSTEOLOGY 


1501 


Maxilla 

Mandible \ Canine tooth 


FIGURE 48-137. Labelled tracing 
of Figure 48-136. 

(From Sis and Getty, 1968 ) 


Temporomandibular jo*fd — 
Foreign body Ibullet)- 
External ocoustic meatus - 
Tympanic bulla 
Hyoid— ~ 

Atlas 

Larynx 

Axis- — ” 

Trachea 





1502 


CARNIVORE 



11 12 13 14 15 16 


FIGURE 48-140 Skull of cat. sagittal section. 

1 Frontal bone 2 nasal bone 3 incisive bone 4 parietal bone 5 cerebral fossa 6 osseous tentorium cerebelll 7 
cerebellar fossa 8 Internal auditory meatus 0 hypoglossal canal 10 tympanic bulla 11 perpendicular plate of ethmoid 
bone 12 olfactory fossa 13 cribriform plate of ethmoid bone 14 sphenoid sinus 15 optic canal 16 processus hamulus 
(From Sis 1965) 



FIGURE 48-141 Skull of cat (with 
dorsal portion of frontal bone removed) 
dorsal view 

1 Frontal sinus 2 dorsal recess of nasal 
cavity (From Sis 1965 ) 




1502 


CARNIVORE 



11 12 13 14 15 16 


1 IGURE 48-140 Skull of rat, sagittal section. 

1 Frontal bone 2 nasal bone 3 Incisive bone 4 parietal bone 5 cerebral fossa G osseous tentorium cerebelll 7, 
cerebellar fossa 8 internal auditor* meatus 0 hypoglossal canal 10 tympanic bulb 11 perpendicular plate of ethmoid 
bone 12 olfactory fossa 13 cribriform plate of ethmoid bone 14 sphenoid sinus 15 optfccana) 1G processus hamulus 
(From Sis 1965) 



FIGURE 48-141 Skull of cat (with 
dorsal portion of frontal bone removed), 
dorsal view 

1 Frontal sinus 2 dorsal recess of nasal 
cavity (From Sis 1965 ) 




48— CARNIVORE OSTEOLOGY 


1503 


BIBLIOGRAPHY 


Andersen. A. C., and M. Floyd 1 963. Growth and development of the 
femur in the beagle. Am. J. Vet. Res. 24:348-351. 

Baum, 1L, and O. Zletztchmann. 1936. Handbuch der Anatomfe des 
Ilundes. Band I. Skelett- und Muskelsyste m Berlin, Paul Pare?. 

Bourdelle, E-, and C. Bressou. 1953. Anatomic rdglonale dei Ani- 
maux Domesttques IV. Carnivores: Chlen et Chat. Parii, J. B. 
Bailliire 

Bradley, O. C„ and T. Grahame. 1959. Topographical Anatomy of the 
Dog. 6th ed .New York, Macmillan Co. 

Bressou, C., N Pomrlaiklnsky-Kobozleff and N. Kobozieff. 1957, 
Etude radiologique de l'osslffication du »quelette du pied du 
Chlen aux divers stades de eon Evolution, de la nalssance & l'4ge 
adulte. Rec. Mfd. VR 133.449-464. 

Bressou, C., N A. Pomriasklnsky-Kobozleff and N Kobozieff. 1959. 
Etude radiologique de l'osslficatlon du squelette de la main du 
Chat. Rec. Mid VR 135 547-555 

Bressou, C., N A. Pomriasklnsky-Kobozleff and N Kobozieff. 1959 
Etude radiologique de l'osslficatlon du squelette du pled du ChaL 
Rec. Mid. VR 135 611-618 

Bronf, A. C^and U. Zfmmert 1951. Anatomla Degli Animal! Domes- 
del 2nd ed. Vol 1. Milano. Casa EdJtrlce Dottor Francesco Val- 
lardL 

Chapman, W L 1965. Appearance of ossification centers and epi- 
physial closures as determined by radiographic techniques. 
J. Am. Vet. Med. Assoc 147:138-141. 

de Beer, G. R. 1937. The Development of the Vertebrate SkulL Lon 
don, Oxford Uni v. Press 

Dyce, K. M-, R. H. A. Merlen and F. J Wadsworth. 1052. The clinical 
anatomy of the stifle of the dog. BriL Vet J 108:346-353. 

Ellenberger, W. 1908. Lelsering’a Atlas of the Anatomy of the Horse 
and the Other Domestic Animals. 2nd ed , Chicago, Alexander 
Eger. 

Habel. R. E., R. B. Barrett, C. D. Dtesem and W. J. Roenlgk. 1963 
Nomenclature for Radiologic Anatomy. J. Am. Vet Med. Aitoc. 

■ 142:38-41. 

Hare, W. C. D. 1958. Radiographic anatomy of the canine skull. J. Am. 
Vet Med. Assoc. 133:149-157. 

Hare, W. C. D 1959a. Radiographic anatomy of the canine pectoral 
limb. Part II. Developing limb. J Am. Vet Med. Assoc. 135.305- 
316. 

Hare, W. C. D 1959b. Radiographic anatomy of the canine pectoral 
limb. Part 1. Fully-developed limb. J. Am. Vet Med. Assoc. 135: 
264-271. 

Hare. W. C. D. 1 959c. Radiographic anatomy of the feline skull J. Am. 
Vet. Med Assoc. 134:349-356. 

Hare, W. c. D. 1960a. Radiographic anatomy of the canine pelvic 
limb. Part I. Fully-developed limb. J. Am. Vet. Med. Assoc 136: 
542-565 

Hare, W. C. D. 1960b. Radiographic anatomy of the canine pelvic 
limb. Part II. Developing limb. J. Am. Vet Med. Assoc. 136.603- 


Harc. W. C. D. 1960c. The age at which epiphyseal union takes place 
in the limb bones ol the dog Wiener Tiertatllche Monatscbrifl: 
224-245 

Hare.W. C. D. 1961a. Radiographic anatomy of the cervical region of 
the canine vertebral column. Part I. Fully-developed vertebrae. 
J. Am. Vet Med. Assoc. J 39.209-220. • 

Hare, W. C. D. 1961b. Radiographic anatomy of the cervical region of 
the canine vertebral column Part II. Developing vertebrae. J. 
Am Vet Med. Assoc. J 39.21 7-220. 

Hare, W. C. D. 1961c. The ages at which the centers of ossification 
appear roentgenogniphically In the limb bones of the dog. Am. J. 
Vet Ret. 22:825-835. 

I layne, II. 1 898. Mammalian Anatomy. Part I. The skeleton of the cat 
Philadelphia, J. B. Llppincott Co. 

Leonard. E. P. 1960. Orthopedic Surgery of the Dog and Cat Phila- 
delphia, W B. Saunders Co. 

Lesbre, M. F. 1897. Contribution 4 l'ftude de l'osslficatlon du tque- 
Jette det mammlKres domesdques principalement aux points de 
vue de sa marche et de sa chronologle. Annales de la Soc. Agric. 
Sci Industrie Lyon 5(7th series): 1-106. 

McFadyean, J. 1953 Osteology and Arthrology of the Domesticated 
Animals. 4th ed. (Edited by II. V. Hughes and J. W. Dranifleld). 
London. BaiUiere, Tindall & Cox. 

Miller, M. E.. C, C. Christensen and If. E. Evans. 1964. Anatomy of 
the Dog. Philadelphia, W. B. Saunders Co 

Pomrlasklnsky-Kobozieff, N. and N. Kobozieff. 1954. Etude radio- 
loglque de 1’aspeci du squelette normal de la main du chien aux 
divers trades de son Evolution, de la nalssance 4 l'dge adulte. 
Rec.Mfd VR, Al/ort 130 617-646. 

Schloithauer, C. F., and J. M Janes. 1652. The time of closure of the 
lower femoral epiphyses and upper tiblal epiphyses in the dog as 
determined by roentgenogram. Am J. Vet Res. 13:90 

Scholtysik, G 1962 DtenormaleZwischenwirbelscheibedesHundes 
notmaler und chondrodystropher Raasen. Inaugural-Dissertation, 
Frelen Universitit Berlin 

Sis, R. F. 1965. Anatomy in feline surgery. Ph D. Thesis, Iowa State 
University Library. Ames. 

Sis. R. F. and R. Cetty 1968 Normal radiographic anatomy of the 
cat Vet Mtd.fSm. Anirn. Clin. 63:475-492. 

Sisson, S 1921 The Anatomy of the Domestic Animals. 2nd ed., 
Philadelphia. W. B. Saunders Co. 

Smith, R N 1959 Protrusion of the inten ertebral disk Brit. Small 
Anim Vet Assoc Congress Proc. 44-51. 

Smith, R. N. I960. Radiological observations on the limbs of young 
greyhound* J. Small Anlm. Pract. 1 :84-00. 

Smith, R. N 1964. The pelvis of the young dog Vet Rec. 76.975- 
979 

Smith, R. N , and J. Allcock. 1 960 Epiphysial fusion in the greyhound. 
Vet Rec. 72:75-79. 

Solis, J. A., and G. C. Orinlon. 1963. More anatomical data on the 
clavicle of the dog Philipp. J vet Med. 2 35-39. 

Vituma, A. 1952. Hyperphalanglsm of an extremely well-developed 
first digit accompanied by an extra dewelaw In the hindpaws of a 
dog. J Am. Vet Med. Assoc. 121 .93-95. 



CHAPTER 49 


CARNIVORE 

SYNDESMOLOGY* 

by S Sisson 


JOINTS AND LIGAMENTS OF THE 
VERTEBRAE 

The nuchal ligament consists of a small fi 
brous band which extends from the spine of 
the axis to the cranial thoracic spines, it may 
be regarded as a mere fibrous raphe between 
the n ght and left mu scles 
There are interspmoua muscles Instead of 
ligaments in the neck. 

There are three ligaments in connection 
with the dens of the axis The two alar Iiga 
ments anse on either side of the dens, diverge, 
and end on either side of the foramen mag 
num. The transverse ligament of the atlas 
stretches across the dorsal surface of the dens 
and binds it down on the ventral arch of the 
atlas, a bursa being interposed. It is attached 
on either side to the lateral mass of the atlas 
The two capsules of the atlantooceipital 
joint communicate with each other, and usual 
ly with the capsule of the atlantoaxial joint 
also 


ARTICULATIONS OF THE THORAX 

The first sternocostal joints do not coalesce 
The sternal ligament divides Into three bands 


*TMi chapter con«l»ts only of a brief itatement of the 
most Important difference* in the Joint* of the carnivore- In 
addition. because of the rime factor the nomenclature has 
not been fully updated with that of the N-A.V (1 968 >. 

1504 


ARTICULATIONS OF THE 
THORACIC LIMB 

SHOULDER JOINT 

The joint capsule communicates so freely 
with the bicipitoradial bursa that the latter 
may well be regarded as a pouch of the cap- 
sule There is a rudimentary marginal carti 
lage around the rim of the glenoid cavity 
There is usually a strong band extending from 
the acromion to the lateral part of the capsule, 
another band often stretches between the 
scapular tuberosity and the acromion. 


ELBOW JOINT 

The joint capsule is reinforced cranially by 
an oblique ligament which arises cranial to 
the lateral condyle of the humerus proximal to 
the joint surface, and joins the terminal part 
of the biceps brachii and brachialis distally 
There is a strong reinforcement of the caudo- 
medial part of the capsule, which extends 
obliquely from the medial side of the olecranon 
fossa to the ulna, just proximal to the anconeal 
process The lateral collateral ligament is 
much stronger than the medial collateral one 
It is attached proximal to the lateral eplcon 
dyle of the humerus and distally chiefly to the 
eminence distal to the neck of the radius, but 
part of It inclines caudally and is attached to 
the ulna. The middle part of the ligament is 
wide, and forms a sort of cap over the proximal 
tuberosity of the radius From this part a band, 
the annlar ligament of the radios, extends 



49 -CARNIVORE SYNDESMOLOGY 


1505 


across the cranial part of the proximal end of 
the radius and ends on the ulna, although in 
corporated in the joint capsule it is easily 
defined The medial ligament is more slender 
It arises from the medial epicondyle of the 
humerus and passes deeply into the proximal 
part of the interosseous space, ending chiefly 
on the caudal surface of the radius, a little 
medial to the attachment of the lateral liga- 
ment, there is also a small attachment to the 
interosseous border of the ulna This ligament 
is very oblique An elastic band (hg olecrani ) 
extends from the lateral surface of the medial 
epicondyle to the cranial border of the ulna 

There are two radioulnar joints The proxi- 
mal radioulnar joint is included in the capsule 
of the elbow, but is provided with an anular 
ligament, as described above The distal radio 
ulnar joint is formed by a concave facet on 
the radius and a convex one on the ulna, and 
is surrounded by a tight capsule The interos 
seous membrane unites the shafts of the two 
bones, its proximal part is especially strong 
and is attached to prominences on both bones 
The movements consist of limited rotation of 
the radius (about 20 degrees), carrying the 
paw with it The ordinary position is termed 
pronation, outward rotation is supination 

These movements are best seen in man In whom the hack 
of the hand may be turned forward (pronatlon) or backward 
(supination) In the dog the rotation is much restricted and 
is freest when the elbow Is flexed 


CARPAL JOINTS 

These have the same general arrangement 
as m the horse Numerous minor differences 
exist, but are excluded from this bnef account 
which contains only important special fea 
tures 

The lateral and medial movements are 
freer, but flexion is not so complete the ana 
tomical explanation of these facts lies m the 
nature of the articular surfaces and ceitam 
ligamentous differences Two oblique, some 
what elastic bands cross dorsal to the radio- 
carpal and intercarpal joints The proximal one 
is attached to the distal end of the radius and 
passes distally and laterally to the ulnar car 
pal bone, the other connects the radial and 
fourth carpal bones in a similar fashion 
There are six dorsal and six palmar hga 
ments The interosseous ligaments are not 
interordinal The accessory carpal bone is at- 
tached by ligaments to the ulna the inter 
medioradlal and the third, fourth and fifth 
metacarpal bones The distal carpal bones are 
attached to the metacarpal bones by dorsal 
and palmar ligaments 

INTERMETACARPAl JOINTS 

The second to fifth metacarpal bones articu 
late with each other at their proximal ends 


and are connected by interosseous ligaments, 
which do not, however, unite them closely, as 
in the horse There are feeble dorsal and pal 
mar ligaments which unite the proximal ends 
of the metacarpal bones 


METACARPOPHALANGEAL 

JOINTS 

There are five metacarpophalangeal joints, 
each having its own capsule and indistinct 
collateral ligaments A small sesamoid bone 
occurs in the dorsal part of each capsule, over 
which the corresponding digital extensor ten 
don plays The intersesamoidean ligaments do 
not extend proximal to the sesamoids The 
phalangosesamoid ligaments are present as 
well as a fibrous layer which attaches the dis 
tal margins of the sesamoids to the palmar sur 
face of the proximal end of the proximal 
phalanx 


I NTERPHALANGEAL JOINTS 

Each joint has a capsule and two collateral 
ligaments The distal joints have also two elas 
tic dorsal ligaments, which extend from the 
proximal end of the middle phalanx to the 
ndge at the base of the distal phalanx They 
produce dorsal flexion of the joint, and thus 
raise or retract the claws when the flexor mus 
cles relax The distal sesamoids are repre 
sented by complementary cartilages attached 
to the palmar margins of the articular sur 
faces of the distal phalanges 

Three mterdigital ligaments restrict the 
spreading apart of the digits (Fig 49-1) Two 
of these cross the palmar surface of the proxi 
mal parts of the chief digits, 1 1 one for the 
second and third the other for the fourth and 
fifth, they blend with the anular ligaments on 
either side The third ligament is attached on 
either side to the foregoing ligaments and to 
the anular ligaments of the third and fourth 
digits, and curves distally centrally, ending in 
the large pad on the paw 


ARTICULATIONS OF THE 
PELVIC UMB 

SACROILIAC JOINT 

This joint and the pelvic ligaments present 
no \cry striking differences except that tht 
sacrotuberal ligament is a narrow but strong 
band which extends from the caudal part of 
the lateral margin of the sacrum to the ischi 
atic tuber, it is the liomologue ol the sucro 
tuberous ligament of man 



1506 


CARNIVORE 



FtfiLKF <9-1 (fffamenU and trndonn of dtRiM of 
doe pelvic limb, plantar »i»w 

a a Supeiful.il 1 Jf 2 lt. 1 l Pexor trndt n b irndjn to Lirse 
!•■<* t lumlmalf* d jnteriHarl v f anulirbeR atnifli 
urv', Ij!.kic'j| I Ini* a auvpenvory lie of UfRe pad It 
ditful atiuLtr fiat i tftep digital ffe*t»f tendon k dittal 
fcraarv»td 1* f>e I trot'atrrjl sesamoid lit m *u*penvjr> 
bi of rfiuul M n digital jud» (I rom Ulrnlwrier and 
Ilium IW ) 


HIP JOINT 

There an* no lmj>ortant difference* 


STIFLE JOINT 

Tlif Joint, in gincra! resembles that of the 
pic The caudal part of the capsule contains 
two sesamoid bones, which are embedded in 
the origin of the gastrocnemius muscle 


TIBIOFIBULAR JOINTS 

The amneement is essential!) the same os 
jn the pic. but there is no interosseous Uca 
ment in the distal joint. Not uncommonly, the 
distal part of the slwft of the fibula and tibia 
areankylosed 


HOCK JOINT 

The long collateral ligaments are \ ery small 
and the short ones double The plantar liga- 
ment is w eak and ends on the fourth metatar- 
sal bone No distinct dorsal ligament is pres- 
ent, unless we regard as such a ligament which 
extends from the neck of the talus to the fourth 
tarsal and third metatarsal bones 
The remaining joints resemble those of the 
thoracic limb 


ARTICULATIONS OF THE SKULL 


TEMPOROMANDIBULAR 

ARTICULATION 

As the articular surfaces are cylindrical in 
cur\ature and the intcrarticular disc is very 
thin, there is practically no transverse or 
gliding mo\ emenk The caudal ligament is ab- 
sent 

The other articulations of the skull are stiff) 
cicntly described in the Osteology chapter 


BIBLIOGRAPHY 


AntuUyotin.C |M Nerve »upply to ibyihnulder elbow carpal hip. 
•tiflr and larval joint* of the dot ii determined hr frost dlate* 
turn Thetis Cornell Unlsertliy Ithaca S»»Vtrt 
Baron* R 1 >*><1 Anathrhl* CornpaiVedrs MammifrrralJometiPiurt 
Tom* II Anhrdofw e* Mycjofle Lyon Laloratolry 6 anatomie 
Frol* Natlnmle Vetthnairr 

Brown R F 1051 A turslral approach to thr coiofrnwnl Joint of 
do<s N Am. \ ft 34 420-421 

Oyer KM R II A M*r!»n and I J W.d..«th 10*2 Thedmleal 
•natomTOf thesofleofil edo* Brit Vet J 104 MS-1M 
Fllentergrr V. and II Baum. JV08 Handbuch dcr ' CT*Jf khendeft 
Anatomic d*» Hduttiere too Aujutt 1 1 rtchwald Berlin 
CarrVli J C and C R. Sullivan l<ttl A leehrUc ot petformln* 
dulofraphy In dot* MajoClinX' Prw 33 3*0-373 
tlorrteln. B F 111] lA<rrvcrtrbr*J disc pttwrotwm In Ih* do* I f/v 
etdyncraod patholo*.* al lesions Am. J Vn Re* M 20O-Z»/> 
Harriet n. B I 1*I5J Immtmlnl disc yrMniuon In liar dot II 
SriwpmrTwioloty and clinical duenotit Am J V*» R»t 14 7*0- 
37* 

Ho*tl**n B 1 1*151. !nt*r*rn*t>rai disc pnarutlwi Jn the do* III 
Ra,).oto*lral d-icnosl, Am J Vrl Rr» 14 2~3-2Vl 
llnrrlnn. R F IW Further evaluation *4 Ih* rr*atm*ni of disc fro 
true ion parj{4*(U in the do* } A \ M A 123 4*>V*1| 

Vin* A S and R S South. Hil A rompanum of ilv rutsinr of 
the mirnrndtil d « In (V-t and mart Ini Vei J 3 115 14 * 
Kin* A S and R. N Smith 19S4 Frwnmwi d tic Ini'nmrM 
d wr in the ral * rt Ree *9 W< 512 
«i« M L OC CFnnmuaindH r Fuiri J9M Anatomy of 
ihcOot W B SavMm Comranr RHinVlyhla 
Mu' i**n.i It IV'* Tli* mnaniilon r( tic btnwrti rnalnd wilif 
of the vertrlea* J Anal VI 415-4*5 
I IM< Maniacal Injuries In dost N Am.Sa* iO VX> 5lf 
•7 man. J IV57 InnnmrtnJ d ic yrotruMir, tn tho ranine le«i 
iU<r tcdl*** Vet 1 9 II 

faeltama. S 1**52 Li lament lajartn In the t antic ♦c'dejcant (Id 

mill etenrvary r t£V|* 

Slimlaf J IVI7 8*vira*e tor settle* hetvden ifumrnie t/fvi tut 

Slat ham* d*» t Aaetslrakea W w her Tier trill Mxutvh 34 
T2S 744 

Smith R V 175A Alulnnail fatvm l«f 4 m jrvlivirn |» 

d. | and man Pr«c R So. Ued SI 5*t~4'l 
Vwh.'.,* K C t W> Serf**! rsmctM of patella* erupts tn Ih* 
do* JAVA) A 134 47MU 



CHAPTER 50 


CARNIVORE 

MYOLOGY* 

by L. E. St. Clair 


PART I -DOG 


CUTANEOUS MUSCLES 

The cutaneous muscles are spread over 
the body as a thin interrupted sheet in the 
superficial fascia In some cases there may 
be more than one layer Skeletal attachment 
is sparse, however 

In the head they consist of the sphincter 
colli supcrficinlis, platysma and sphincter 
colli profundus. The sphincter colli super- 
ficialis consists of sparse transversely oriented 
fibers scattered from near the sternum to the 
hyoid region. The platystna is a well-developed 
sheet of irtuscle extending from the dorsal 
raphe of the neck ventrally and rostrally and 
ventral to the ear to fuse with the facial mus- 
cles nt the comer of the mouth (Fig. 50-1) 
Deep to the platysma on the cheek and ventral 
to the ear is the sphincter colli profundus, 
which includes oral, palpebral, intermediate 
and nurlcular portions. The fibers are, In gen- 
eral, transversely oriented The specific mus- 
cles of the face associated w itii and developed 
from this muscle will be considered Later. Ov er 
the Lateral and some of the ventral and dorsal 
portions of the thorax and abdomen is the 
cutancus trunci. It stretches from the gluteal 
region ventrad and cranlad to fuse with the 
pectoralis profundus caudal to the axilla. 
Parallel longitudinal fibers extend ns far 
dorsad as the vertebral column Ventrally 
Its fibers form the fold of the ilank and turn 
medially 10 approach those of the other side 
c.utd il u> the sternum Slips from the cuta 
ncus trunci form the preputinlU in the male 
and the medial edges course deep to the mttn 


mary glands somewhat as the supramam- 
marius m the female The cutaneus trunci is 
innervated by the lateral thoracic nerve 


MUSCLES OF THE HEAD 

(Musculi Capitis) 

Arranged about the first cervical verte- 
bra deep to all the other muscles and attach- 
ing to the skull are several relatively small 
muscles which include the longus capitis, 
rectus capitis ventrahs. rev t us capitis later- 
alis, rectus capitis dorsalis major, rectus 
capitis dorsalis minor and ohhquus capitis 
crnnialis. The obliquus capitis caudnlis tov 
ers the axis and atlas dorsally, arising on the 
spineof the axis and runningobliquelv cranio- 
latcrally to insert on the wing of the atlas 
The rectus capitis vcntralis is deep to the 
longus capitis and inserts with it on the basal 
part of the occipital bone but arises onlv as 
far caudad as the atlas, whereas the longus 
capitis arises from the transverse processes 
as far as the sixth cervical vertebra The 
right and left muscles in the neck are separ- 
ated by the longus colli. Lateral to the rostral 
portions of these muscles is the rectus capitin 
lateralis, which stretches from the wing #>f 
the alias to the jugular process These mus- 
cles ilex the ntlnntooccipii.il joint The tccil 


Tbr mu« lr« arc In tcnci <1 m the «>»»W list c*j 

in .Nppiim.j Anutumifu VrlrUnni' VV|j. t« It *»H *t |W« 
A*c tlactd In truupt on the tun, rt rrOrwon 
mom and tnr-r».m m 


1507 



1508 ^ 


CARNIVORE 



t M f nulls 2 orbicularis oris 3 levator nasolabUlis 4 aphlncter colli profundus 4 nularis 5 orbicularis oculi 6 
levator an tull oeull medulla 7 frontalis 8 auricular** rostral** 9 retractor an eull oculi lateralis 10 tygomaUcus 11 
auricular** ventrales 12,auricularei caudale* 13 platysma 14 sphincter colli superficial^ 15 atemobyoideu* 16 ater 
noctphalleus 17 17 fcraehiocephallcui 18 omotrnnsvervarius 19 suprasplnatus 20 terra tus vent rails cervlcis 21 
21 trapetlus 22 Infraspinatus 23 23 deltoideus 24 bnchlalis 25 extensor carpi radialis 26 anconeus 27 27 
tricep* brachli 28 cuwneus truncl 29 larisslmus dortl 30 pectorall* profundu* 31 rectus abdominis 32 intercostale* 
extern! 33 obUquus externu* abdominis 34 aanorius 35 tensor fasciae latae 36 gluteus tnedius 37 gluteus luperfl 
cUlls 38 sacrocaudalis dorsalis (lateralis medlalis) 39 imertransversartl caudae 40 lacrocaudalls ventralls (lateralis 
meduiis) 41 bicep* femori* 42 *emitendlnosu* 43 *emlmembrano»us- 


dorsalcs muscles Insert on the occiput The 
major muscle arises on the spine of the axis 
and the minor and deeper one attaches to the 
atlas The obliquus capitis cranlalis arises 
on the dorsal surface of the wing of the atlas 
and courses dorsomedially to insert on the 
nuchal line and the mastoid process These 
muscles extend the atlantooccipltal joint The 
obliquus capitis caudalis rotates the atlanto- 
axial joint The members of this group of mus 
cles are supplied by dorsal or \ entral branches 
of the cervical spinal nerves depending on 
their position and extent 
The following muscles have often been 
considered as parts of the sphincter colli 
profundus the orbieulans oris is the sphlnc 
ter muscle of the mouth and lies in the lips 
A number of other muscles Insert by blending 
with the orbicularis oris The incisiTUs maxtl 
juris and Jncisivus mandibulam are located 
on the alveolar borders of the bones con 
tainlng the Incisors They lie next to the mu 
cosa and extend to the orbicularis oris They 
raise and depress the respective lips The 
levator labil maxillaris and canlnus lie next 
to each other like two parts of a single muscle 
The former is dorsal and arises near the infra 


orbital foramen It courses rostrad as a flat 
band to spread out in the nasal alae and upper 
lip The latter is the ventral somewrhat weak 
er portion and is more a part of the upper 
lip Both are under cover of the levator naso- 
lablahs (Fig. 50-3) Together they dilate the 
nostril and raise the upper lip The buccinator 
forms the cheek. It consists of buccal and 
molar portions The buccal portion is dorsal 
and arises from the maxilla partially deep to 
the masseter The fibers In several planes 
curve rostroventrally to mingle with the 
orbicularis The molar portion is ventral and 
arises from the molar portion of the mandible 
The caudal fibers are deep to the masseter 
As the fibers turn dorsad and rostrad they 
intertwine with the dorsal portion. Super 
ficlal rostral extensions lie deep to the orbic 
ularis Contraction of the buccinator causes 
the cheek to move medially The mehtaHs 
consists of fibers radiating into the lower 
lip from the body of the mandible it stiffens 
the lower lip The vertical fibers ascending 
to the lower eyelid and acting to depress It 
constitute the malaria. Coursing ventrad 
and rostrad from the scutulum to the angle 
of the mouth is a band of muscle, the xygomat 


50 -CARNIVORE MYOLOGY 



FIGURE 50-2. Deep muscles of the head and neck of the dog; lateral view. 


l.xnentaUs, 2, orbicularis oris; 3, 3', buccinator, 4,canlnus, 5, levator labii maxillaris, 6, levator nasolablahs, 7, malaria, 
8, orbicularis oculi, 9, retractor angull oculi lateralis, 10, levator anguli oculi medialts, 11, frontalis, 12, temporalis; 13, 
zygomaticus, 14, massetcr, 15, digastricus, 16, mylohyoldeus, 17, geniohyoideus, 18, hyoglossus, 19, stylohyoideus; 20, 
hyopharyngeus, 21, thyropharyngeus, 22, thyrohyoid eus, 23, stemothyroideus, 24, stemohyoldeus, 25, 25', sternocepha- 
licus, 26, longus capitis, 27, 27’, scalenus dorsalis, 27*. scalenus medius, 28. Intertransversam, 29, serratus vent rails cer* 
vicis, 30, 30’, longissimus (cervicis capitis), 31, 31', semispinalis capitis (biventer cervicis, complexus), 32, obliquus 
capitis caudalis, 33, obliquus capitis cranialis; 34, rectus capitis lateralis, 35, omotransversarius, 36, splenius 


icus. It dips deep to the malaris and inserts 
into the orbicularis. It draws caudad the angle 
of the mouth. Caudally in the same plane are 
the aunculares ventrales muscles. 

The muscles of the orbit, forehead and 
rostral portion of the ear constitute a muscle 
complex (Figs 50-3 and 4), The orbicularis 
oculi is the sphincter of the eyelids. Its dor- 
sal portion is really continuous with the 
frontalis, which runs as flattened bundles 
between the scutiform cartilages. A portion 
of the frontalis curves rostrad from the scutu- 
lum to dip beneath the upper portion of the 
orbicularis oculi and attaches to the orbital 
ligament. The frontalis fixes and pulls the 
scutulum rostrad. The retractor anguli oculi 
lateralis arises from the temporal fascia cau- 
1 dal to the lateral canthus of the eye and runs 
rostrad as a narrow band to bury itself in the 
orbicularis oculi. Its action Is 1 implied by its 


name. The levator anguli oculi medialis (cor- 
rugator supercilii) courses from the naso- 
frontal fascia rostromedially to join the orbic- 
ularis toward the medial canthus. It lifts 
the medial portion of the upper eyelid. The 
levator nasolabialis is a flat, broad but thin 
muscle stretching from the frontal region 
between the orbits to widen as it attaches to 
the nose and upper lip (Fig. 50-4) The fibers 
continue to arise along the nasal bone near 
the midline and course in a rostrolateral di- 
rection. They mingle with the fibers of the 
orbicularis oris, buccinator and caninus. The 
action is to raise the upper lip and increase the 
diameter of the naris. 

The muscles of the external ear are divided 
into four groups (Fig. 50-l)/The auricularCs 
rostrales consist of the scutuloauriculares 
Buper/icJnles, scufuloauricuiares profundi, 
frontoscutularis, zygomaticoscutularis, and 



1510 


CARN1VORF 



FIGURE 50-3. Intermediate museles of the head neck and thorax of the do* lateral view 

l Frontalis 2 aurtculares rostrales 3 retractor angull ocull lateralis 4 levator angull oculi tned ali* 5 orbicularis 
oculi 6 levator nasolabialls 7 levator labli maxillaris 8 canlnus 9 orbicularis oris 10 menialls 11 buccinator 12 
sphincter colli profundus 12 malaris 13 aurtculares ventrales 14 nuriculares caudales 15 rhomboideus 1G splenlus 
17 17 17* 17 longitsitnus (lumborom thoracis cervicls capitis) 18 18 serratus ventralis (cervids thoracis) 19 
omotransversarius 20 intertransversaril 21 sternocephallcus 22 stemohyoideus 23 pectorales guperfidales 24 pec 
toralis profundus 25 rectus thoracis 26 26 scalenus dorsalis 26 scalenus medlus 27 intercottales extern! 28 
rectus abdominis 29 obliquus externus abdominis 30 serratus dorsalis cranialis 31 iliocostalis 32 serratus dorsal s 
caudaiis 33 obliquus intemus abdominis. 


zygomaticoauriculans. The aurtculares dor 
sales include the interscutulans parieto- 
scutulans and panetoauricularis The auncu 
lares caudales are derivatives of the platysma 
they consist of the cervicoscutulans cervieo- 
auncularis Buperiiciahs cervicoaunculans 
medius and cervicoaunculans profundus The 
aunculares ventrales include the styloau 
nculans and parotidoauriculans Except for 
the ventral group the influence of the mus 
cles on the concha is enhanced by their at 
tachment to the scutulum 
The muscles of the face orbit and external 
ear and the cutaneous muscles of the head 
are supplied by the facial nerve The deep 
facial muscles discussed next are also sup- 
plied by the facial nerve The stapedius is in 
the middle ear The digastncus arises on the 
jugular process of the occiput and inserts 
on the ventral border of the mandible (Fig 
50 2) A tendinous intersection indicates the 
digastric nature of the muscle The caudal 
belly belongs to the g roup supplied by the 
facial nerve but the rostral belly is supplied 
by the mandibular nerve It depresses the 
mandible Over the lateral surface of the cau 
dal portion of the digastncus runs a small 
muscular band the stylohyoideus It stretches 
from the proximal portion of the stylohyoid 
to the basihyoid which it raises The occipito- 


hyoideus is a very small triangular muscle 
which extends from the jugular process to 
the proximal end of the stylohyoid which 
it retracts 

The four muscles of mastication (those that 
close the jaw) are supplied by the mandib- 
ular nerve The masseter forms a prominent 
bulge on the lateral surface of the vertical 
part of the mandible (Fig 50-2) Its surface 
is aponeurotic and tendinous inscriptions 
are present throughout its depth There are 
three layers each arising from the zygomatic 
arch Although the fiber direction is some 
what different in each layer the general 
direction is caudoventral to attach over the 
masseteric fossa The boundnes project some- 
what beyond the edges of the mandible The 
temporalis fs a very large bulging muscle 
which occupies the entire temporal fossa 
Its fibers course ventrad to surround the coro- 
noid process as they insert It is covered by 
the superficial muscles and contacts the 
other muscles which close the jaw at its in 
sertion Whether the right and left muscles 
contact each other dorsally depends on the 
position of the temporal line and sagittal 
crest Connective tissue gives a glistening 
appearance to the surface of the muscle At 
the level of the tip of the coronoid process 
a curved bundle of fibers sweeps rostrad 



1511 


50 -CARNIVORE MYOLOGY 


from the nuchal line to blend with the main 
portion of the temporalis. The pterygoideus 
medialis occupies a large portion of the 
pterygopalatine fossa, having arisen from the 
pterygoid, palatine and sphenoid bones. The 
fibers course caudolaterally to insert on the 



medial surface of the mandible near and in- 
cluding the angular process. Ventral to the 
mandible it forms a fibrous raphe with the 
masseter. The portions of the mandibular 
nerve directed toward the mandibular fora- 
men course between the pterygoidei medialis 
and lateralis. The maxillary artery and nerve 
cross the portion in the pterygopalatine fossa. 
The pterygoideus lateralis is a much smaller 
muscle which arises from the sphenoid just 
rostral to the row of foramina. It passes ven- 
trolaterally to insert on the medial surface of 
the condyle of the mandible and adjacent por- 
tion of the articular disc. Its fibers cross the 
dorsal portion of the pterygoideus medialis. 


Extrinsic Muscles of the Tongue 

(Fig. 51-3) 

The styloglossus arises along most of the 
extent of the stylohyoid (Fig. 50-5). It passes 
rostroventrally as a wide band of fibers which 
is separated into long, short and rostral por- 
tions to insert into the ventral portion of the 
tongue. The action is to retract the tongue. 
The hyoglossus arises from the basihyoid 
and the adjacent portion of the thyrohyoid. 
It courses rostrodorsally as a wide band of 
fibers dipping deep to the styloglossus to join 
the base of the tongue. It retracts and de- 
presses the tongue. The genioglossus consists 
of a triangular sheet of muscle arising from 
the medial surface of the mandible just cau- 
dal to the body of the mandible and spreading 
into the tongue in a sagittal plane. Ventrally 
the right and left muscles are separated by 
the geniohyoideus muscles, but in the tongue 
they lie next to each other. The action in gen- 
eral is to depress and protrude the tongue. 
The hypoglossal nerve supplies the muscles 
of the tongue. 


FIGURE 50-4. Epaxial muscles or the dot:; dorsal 
Tie*'. 

1, Levator nasolabial!*, 2, orbicularis oculi, 3, levator 
anguti oculi medialis, 4, frontalis, 5. S’, atirfculxres ros- 
trale*, 6, auricular** cau dales, 7, 7\ 7% rhomboldeu* (ea- 
pitl*. cervlci*. thoraei*), 8. tplenlui. 6. O’, *cnratu» ven- 
tral!* (cervlci*. thoraei*), 10, tupra*pinatui, 11 , 
Infra* plna tut; 12, tere* major. 13, *erTatu» doraall* cran- 
ial!*. 14, *erratu* donalj* raudaljs, J5, Intercostal** ex- 
tern!; 16. multifidi. 17, tacroeaudall* dorsalis medialis, 16. 
tacrocaudal!* doraall* lateral!*, 10 . intertranivrraaril dor- 
tale* caudie, 20 . 20 *. 2 £T, 20 ~. longitttmut (lumborvm. 
thoraei*. cervlci*. capitl*). 21, »pinaU», 22. UlocotwU*. 23 , 
23% temlspinaU* capitl* (biventer Cervlci*. complexut), 
24, auricular** donate*. 25. retractor annuli oculi la 
trail*, 26, masteler, 27. I era tor labli ma*lU*rt«. 28. 
caninu* 



CARNIVORE 


Extrinsic Muscles of the Pharynx 

(Fig 50-2) 


The hyopharyngeus consists of two parts 
which when considered separately, are 
ceratopharyngeus and chondropharyngeus 
The hyopharyngeus in general arises from 
the thyrohyoid and ceratohyoid The fibers 
form a band which passes dorsally in the 
wall of the pharynx to meet the muscle of the 
other side in the median dorsal raphe The 
thyropharyngeus lies caudal to the hyopharyn- 
geus and arises from the lateral surface of the 
thyroid cartilage to insert on the median dor 
sal raphe It forms a considerable portion of 
the wall of the pharynx. The cricopharyngeus 
is the caudal muscle of the group It anses 
from the lateral surface of the cricoid carti 
lage of the larynx and spreads out as it in 
serts on the median dorsal raphe to blend 
into the esophagus These muscles are con 
stnctors of the pharynx. 

The palatopharyngeus and pterygopharyn- 
geus are relatively long but thin muscles 
which arise from a rostral position and s\veep 
over the pharynx to insert on a median dorsal 
raphe The fibers of the palatopharyngeus 
are not densely packed as they course from 
their origins on the soft palate The pterygo 
pharyngeus is dorsal and somewhat super 
ficial to the palatopharyngeus Its fibers are 
more closely packed and anse from the ptery 
gold hamulus These muscles constrict the 
pharynx somewhat and draw it rostrad The 
constrictors of the pharynx are supplied by 
the vagus nerve 

The stylopharyngeus caudahs is a small 
muscle which dilates and elevates the phar 
ynx. It extends from the stylohyoid to the 
rOstrodorsal wall of the pharynx where the 
fibers spread out to be associated with those 
of the palatopharyngeus It is supplied by the 
glossopharyngeal nerve 


Muscles of the Soft Palate 

The^tensor veil palatini is a small band of 
muscle which arises from the muscular proc 
ess of the temporal bone It courses rostro- 
ventrally to turn around the pterygoid hamu 
lus and disperse into the soft palate It is 
tendinous as it contacts the hamulus The 
faction, as the name implies, is to tense the 
soft palate It develops as a slip from the 
pterygoids and is thus supplied by the man 
dlbular nerve The levator veil palatini is a 
slightly larger band arising near the tensor 
and passing ventrally between the protrac- 


tors of the pharynx to insert into the caudal 
portion of the soft palate, which it raises The 
palatinus constitutes the main substance of 
the soft palate Its fibers attach rostrally to 
the palatine process of the palatine bone and 
are oriented longitudinally in the soft palate 
The last two muscles are supplied by the 
vagus nerve Th e levator veil palatini, tensor 
veil palatini and pterygopharyngeus form a 
small triangle on the side of the nasopharynx. 


Intrinsic Muscles of the Larynx 

The encothyroideus is innervated by the 
external branch of the cranial laryngeal 
branch of the vagus The other muscles of 
the larynx are innervated by the recurrent 
laryngeal branch of the vagus The cnco- 
thyroideus is a thick but not extensive muscle 
which runs rostrodorsally from the ventro- 
lateral portion of the cncoid cartilage to at 
tach to the caudal portion of the thyroid carti 
lage It lies deep to the insertions of the 
stemohyoideus and stemothyroideus The 
action is to tense the vocal folds The cnco- 
arytenoideus dorsalis is spread over the dor 
sal surface of the cncoid cartilage The fibers 
run rostrolaterally over the cncoarytenoid 
joint to converge on the muscular process 
of the arytenoid cartilage The action is to 
abduct the arytenoid cartilage and the vocal 
fold The cncoarytenoideus lateralis anses 
from the lateral surface of the cncoid carti 
lage and courses rostrodorsally to insert on 
the muscular process of the arytenoid carti 
lage near the cncoarytenoideus dorsalis It 
adducts the vocal fold The thyroarytenoideus 
is the muscle mass which lies medial to the 
lamina of the thyroid cartilage from which it 
arises near the ventral midline Its fibers 
pass caudodorsally to insert on the arytenoid 
cartilage at the raphe of ongin of the ary 
tenoideus transversus Its action is to relax 
the vocal folds by pulling the arytenoid carti 
lage ventrally Deep to and associated with 
the thyroarytenoideus are two vertically 
oriented muscles the vocahs lies lateral and 
caudal to the vocal fold and ligament, and 
the vestibulans (N A V m ventncularis) 
lies dorsal to the vestibular ligament from the 
cuneiform process to the interarytenoid carti 
lage Between the two muscles is the laryn 
geal ventricle, which leads to the saccule 
The vocalis relaxes the vocal folds and the 
vestibularis dilates the saccule The ary- 
tenoideus transversus lies caudal to the vestib- 
ularis and stretches from the muscular proc 
ess of the arytenoid cartilage to the dorsal 
midline Jt adducts the vocal fold. 



50-CARNIVORE MYOLOGY 


1513 


Hyoid Muscles 

(Figs. 50-2 and 5) 

The stylohyoideus and occipitohyoideus 
have been described with the deep muscles 


of the face since they are supplied by the 
facial nerve. The other hyoid muscles he in 
various innervation packages The mylohy- 
oideus is innervated, as is the rostral belly of 
the digastricus from the mylohyoid branch 


FIGURE 50-5. Muscles of head, neck and 
thorax of dog; ventral view. 

1, Masscter, 2, dlgastricus, 3, mylohyoideus, 
4, stemohyoldeus, 5, stcmocephalJcus, 6, 6', 6*. 
■taanhlxrepihafcuv' vtotaWaa'vvrt.'JQiir, ciViWnrnnr 
toldeus, cleldobrachlalls), 7, triceps brachll, 8, 
brachialis, 9, biceps brachll, 10, 10’, pectorales 
superficial™, 11, pectoraUs profundus, 12, del 
toideut, 13, subscapularis, 14, lupraspinatus, 
15, omotransvemrius, 16, trapezius, 17, 17', 
17*, scalenus (dorsalis, medius, ventralis), 18, 
lntertransversoril, 19, longus capitis, 20, ster- 
nothyroldeus, 21, cricothyroldeus, 22. thyro- 
hyoldeus, 23, hyoglostus, 24, styloglossus, 25, 
tenloglossus, 26. geniohyoldcus. 




CARNIVORE 


1514 

of the mandibular nerve It Is ventral in the 
intermandibular space It arises along the 
medial side of the cheek tooth portion of the 
mandible to Insert with the muscle of the 
other side on a median raphe from near the 
body of the mandible to the basihyold This 
thin sheet of muscle forms a sling for the 
tongue It raises the floor of the mouth and 
protracts the hyoid apparatus 
The geniohyoideus consists of a fusiform, 
longitudinally oriented group of fibers on 
each side of the midline deep to the mylo- 
hyoideus and extending from the body of the 
mandible to the basihyold It draws the basi- 
hyoid rostrad and is supplied by the hypo- 
glossal nerve The ceratohyoideus is a plate 
of muscle in the angle between the thyro- 
hyoid and the ceratohyoid It decreases the 
angle between these bones It is supplied by 
the glossopharyngeal nerve The thjrohy- 
oideus arises from the lamina of the thyroid 
cartilage and courses rostrally as a flat band 
to insert on the thyrohyoid Its oblique at- 
tachments make the dorsal fibers much short- 
er than the ventral ones It decreases the dis- 
tance between the hyoid apparatus and the 
larynx. The stemohyoldeus is a long strap- 
like muscle arising from the cranial portion 
of the sternum to run ventral to the trachea 
beside the muscle of the other side to insert 
on the basihyold It is fused laterally and deep- 
ly in the caudal third of the neck with the 
8temothyroideus. The latter, although not 
truly a hyoid muscle, is included here because 
of its relationship to the sternohyoideus The 
stemothyroideus swings laterally in the cranl 
al part of the neck to insert on the lateral 
surface of the thyroid lamina of the larynx 
jn5l caudal tp the nrigio of she IhyrabycwJe us 
It is weaker than the stemohyoldeus Both 
the stemohyoldeus and stemothyroideus 
tend to have a transverse fibrous intersection 
where they separate from each other They 
draw the larynx, hyoid apparatus and tongue 
cavdaily The last three muscles are supplied 
by the first cervical nerve (and perhaps the 
second cervical nerve) through the ansa hypo- 
glossi and ansa cervicalis 


Extrinsic Muscles of the Eyeball 

There are two oblique and four rectus mus- 
cles in addition to the retractor bulbu As- 
sociated with these, but inserting in the upper 
eyelid, is the levator palpebrae supenons All 
but the obhquus verttrahs muscle arise from 
the area about the optic and orbital foramina 
(fissures) All are encased in the penorbua. 
The obhquus ventrahs arises on the medial 
side of the maxillary foramen from a small 
' depression It passes laterally superficial to 
thfe insertion of the rectus ventralis to insert 


deep and superficial to the rectus lateralis onto 
the sclera It becomes wider and flatter to- 
ward its insertion The eyeball is rotated by 
this muscle The ventral part moves medially 
and dorsally and the line of vision is dorsad 
and laterad The obiiquus dorsalis lies medial 
in the orbit and passes forward from its ori- 
gin to form a long, round tendon which passes 
around the trochlea to course dorso laterally 
under the tendon of the rectus dorsalis to 
insert on the sclera lateral to the rectus dor- 
salis The muscle and tendon arc slender The 
eyeball is rotated The dorsal part moves medl 
ally and ventrally and the line of vision is 
ventrad and laterad The recti are arranged 
as four relatively long muscles, dorsal, 
medial, ventral and lateral in position 
from theJr origins about the optic foramen 
they pass forward to spread out somewhat as 
they insert on the sclera at the equator of the 
eyeball Their action on the eyeball is dic- 
tated by the position of the individual mus- 
cles Acting together they retract the eyehalJ 
As the recti diverge from origin to insertion 
the intervals are filled in by the retractor 
bulbi. The origin is lateral to the optic nerve. 
Farther forward the muscle bundles tend to 
form dorsal and ventral pairs The insertions 
arc somewhat caudal and deep to those of the 
recti The action is as the name implies The 
slight levator palpebrae supenons arises 
with the obiiquus dorsalis and rectus dorsalis 
muscles It runs forward between them to 
become the most dorsal muscle of the group 
and to spread out in the upper eyelid It lift® 
the upper eyelid Various slips or patches of 
smooth muscles are associated with the eye- 
ball, eyelids, orbit and striated muscles The 
rectus lateralis and the retractors are Sup- 
plied by the abducent nerve The obiiquus 
dorsalis is supplied by the trochlear nerve All 
the other extrinsic muscles of the eyeball re- 
ceive oculomotor innervation 


Fascia of the Head 

The superficial fascia lies directly beneath 
the skin, encloses the cutaneous muscles imd 
may be filled with fat It may take the na m e 
of the region which it covers The deep fascia 
invests the deep muscles of the head and the 
major salivary glands It hes beneath the 
large superficial vessels and is anchored to 
the prominences 


MUSCLES OF THE NECK 

(Musculi colli) 

The splemus (capitis et cervieia) is a large 
muscle which hes dorsolateral and suf>er- 



50-CARNIVORE MYOLOGY 1515 


ficial in the neck from the thorax to the skull 
It arises from the cranial edge of the tho- 
racolumbar fascia and, thus, from the first 
few thoracic vertebrae The fibers are directed 
ventrolaterally to insert along the dorsal 
nuchal line of the occipital bone and the mas 
toid portion of the temporal bone Fibers 
arise along a dorsal median fibrous raphe as 
far craniad as the atlas Thus, the longest 
bundles are those along the ventral edge of 
the muscle Caudally it is covered by the ser- 
ratus dorsalis and rhomboideus, cranially by 
the stemo occipitalis and cleidocervicahs 
Deep to it is the.semispinahs capitis It is an 
extensor of the head and neck 
The brachiocephahcus extends as a long 
flat muscle between the arm and the neck 
and head (Figs 50-1 and 2) In the caudal 
part of the neck it forms the dorsal boundary 
of the jugular furrow Just cranial to the 
shoulder the muscle is intersected trans 
versely by a narrow tendon which connects 
medially and ventrally with a vestigial clav- 
icle Even though the muscle in the dog ex 
tends from the arm to the head, the clavicular 
tendon is still designated as the origin of the 
parts, which are the cleidobrachialis and 
clcidocephalicus. The cleidobrachialis is a 
band coursing across the point of the shoul 
der from the clavicular tendon to attach with 
the pectorales superficiales on the curvedcrest 
ventral to the deltoid tuberosity of the hu 
merus From the clavicular tendon to the head 
and cranial part of the neck is the cleido- 
cephalicus, which consists of a lateral and 
superficial part, the cleidocervicahs and a 
smaller deep band, the cleidomostoideus The 
former spreads out as it goes cranially over 
the neck to insert on the fibrous raphe of the 
first half of the neck cranial to the cervical 
part of the trapezius and superficial to the 
splenius The latter dips deeply to the cleido- 
cervi calls and stemo-occipitalis to insert 
with the stemomastoideus on the mastoid 
portion of the temporal bone The entire mus 
cle acts as an extensor of the shoulder 
The Btemocephahcus arises on the manu- 
brium of the sternum with the muscle of the 
opposite side The right and left muscles 
diverge as they course craniad (Fig. 50-2) 
Superficially is the cutaneus colli Crossing 
the muscle obliquely is the external jugular 
win, which makes an impression in the mus 
cle Cranially the muscle divides into the 
stcmo-occipltahs, which inserts on the dor 
sal nuchal line and lies cranial to the cleido- 
cervicalis, and the stemomastoideus, which 
dips deeply to insert on the mastoid part of 
the temporal bone with the cleidomastoideus 
Between the stemocephalicus and the brach- 
iocephalicus cranial to the pectorales super- 
ficiales is a depression which contains the 


caudal portion of the external jugular vein 
The stemocephalicus flexes the neck 

The longus colli consists of bundles of fi- 
bers, each of which spans one or more verte- 
brae They He next to those of the opposite 
side ventral to the vertebral bodies from the 
sixth thoracic vertebra to the atlas (Fig 50-6) 
The thoracic fibers anse on the vertebral 
bodies -ventrally and course cramolaterally 
to insert on the transverse processes of the 
seventh and sixth cervical vertebrae The 
four cervical bundles anse on the sixth to 
third transverse processes and run cramo- 
medially to attach to the ventromedial por- 
tions of the bodies one or two vertebrae crani- 
ad The action is to flex the neck 

The scalenus dorsalis and scalenus medius 
form a triangle from the last four cervical 
transverse processes to the first few nbs (Figs 
50-2, 3 and 5) The scalenus ventralis is absent 
The scalenus dorsalis extends caudally from 
the fourth and fifth cervical transverse proc- 
esses as two flat bands One attaches to the 
third or fourth nb where it lies deep to fibers 
of the serratus ventralis The other longer 
ventral band attaches to the sixth to eighth 
nbs The scalenus medius consists of a band of 
fibers ventral to the dorsalis from the fifth 
cervical transverse process to a tubercle on 
the cranial aspect of the first nb and two or 
three muscle bundles deep to that portion of 
the medius and the dorsalis These fibers run 
between the last two cervical transverse proc- 
esses and the first nb The action is to draw 
the nbs craniad in inspiration 

The splenius is supplied by dorsal branches 
and the longus colli and scalem by ventral 
branches of cervical and thoracic nerves The 
stemocephalicus and cleidocephalicus are 
supplied by cranial nerve XI The cleidobrachi- 
ahs is innervated through the brachial plex- 
us 

The deep cervical fascia has pretracheal 
and prevertebral laminae The carotid artery 
and its associated structures are invested by 
the carotid sheath 


DORSAL MUSCLES 

The trapezius is a superficial, fiat, triangular 
muscle consisting of cervical and thoracic 
parts which are continuous with each other 
(Fig 50-1) It arises from the median fibrous 
raphe of the neck and the supraspinous liga- 
ment of the thorax from the third cervical 
vertebra to the ninth thoracic vertebra. The 
fibers converge to insert along the spine of 
the scapula above the acromion A tendinous 
band along the insertion tends to divide the 
muscle into two parts The thoracic portion 



CARNIVORE 


1516 

does not Insert as far distally on the spine of 
the scapula as the cervical portion Cranial 
to the cervical origin is the cleidocervicalis, 
and covering the caudal portion of the tho- 
racic origin is the cutaneus truncl The 
shoulder is raised and advanced by this mus 
cle It is supplied by cranial nerve XI 
The omotransversanus is a band like mus 
cle which attaches to the acromion and the 
spine of the scapula as far as the trapezius 
(Fig 50-5) It courses cranlad, dipping deep 
to the cleidocervicalis to attach to the caudal 
portion of the wing of the atlas When the 
neck is fixed, it draws the shoulder cranlad 
It is supplied by cranial nerve XI 
The Jatissimus dorm Is a fan shaped mus 
cle which arises from the superficial lamina 
of the thoracolumbar fascia and the last two 
or three nbs (Fig 50-1) Its fibers converge 
cram oven trail y and pass medial to the arm 
to insert on the teres major tuberosity of the 
humerus with the teres major This portion 
lies along the dorsal edge of the pectoralls 
profundus More caudally it is covered by the 
cutaneus mmcL The latisslmus dorsi flexes 
the shoulder joint and is supplied by the tho 
racodorsal nerve through the brachial plexus 
The rhomboideus has three portions, tho- 
racis, cervicis and capitis (Fig 50-4) It lies 
deep to the trapezius with its origin stretch 
ing along the dorsal median raphe of the neck 
and the thoracic spines The parts insert along 
the vertebral border of the scapula. The 
rhomboideus thoracis arises from the tho- 
racic spines directly above the scapula. The 
more cranial fibers run caudoventrally, but 
the last fibers are vertical and longer as the 
vertebral border of the scapula at that point 
is farther From the vertebral spines The 
rhomboideus cervicis arises as far cranlad 
as the second or third cervical vertebra and 
is continuous with the thoracic portfon at the 
third thoracic spine The fibers are decidedly 
caudal in direction The rhomboideus capitis 
is a small slip which is separated by a short 
interval from the cervical portion especially 
near the origin It anses from the occiput 
The cranial portions of the rhomboideus are 
covered by the stemo-occipitahs and cleido- 
cemcahs It elevates the shoulder and draws 
it craniad and against the trunk It receives 
the appropriate ventral branches of the cer 
vical and thoracic nerves 

The serratus ventralis cervicis Is described 
with the serratus ventralis thoracis of the 
thoracic muscles 

The serratus dorsalis consists of two mus 
cles, craniahs ai\d caudalis, which arise from 
the ventral edge of the thoracolumbar fascia 
and cross over the longissimus and Iliocostal 
is to insert on the nbs (Figs 50-3 and 4) The 
fibers of the serratus dorsalis craniahs course 


caudoventrally to insert on ribs 2 to 10 The 
serratus dorsalis caudallft consists of three 
bundles which course cranio ven trolly to In 
sert on ribs 11, 12 and 13 The muscles are 
thus separated by a short interval The cranial 
muscle pulls the ribs craniad In Inspiration 
while the caudal muscle draws the ribs cau- 
dad in expiration They are supplied by inter 
costal nerves 

The erector spinae includes the illocostalis, 
longissimus and spinalis. These are cpoxial 
muscles placed In that order from lateral to 
medial dorsal to the ribs and transverse proc- 
esses They arc extensors of the vertebral 
column and fill in the area from the ilium to 
the cranial cervical vertebrae The lumbar, 
thoracic and cervical portions arc oriented 
as longitudinal prolongations of each parent 
muscle They arc supplied by the dorsal 
branches of the spinal nerves The iliocostalis 
lumborum is separated from the lateral por 
tion of the longissimus by only an intermus 
cular septum The fascicles arise from the 
crest of the ilium and the septum to course 
craniolaterally to end after a vertebra or two 
on the lumbar transverse processes and fi 
nally on the last few ribs The fascicles 
come narrow and separate from the Iontjissl 
mus as the ihoeostalis thoracis These bundles 
are directed craniolaterally over several verte- 
brae and ribs to insert on the ribs and finally 
on the transverse process of the seventh 
cervical vertebra. Each tendon near Its in 
sertion is quite distinct, which is character 
istic for this muscle The longissimus fascl 
cies also course craniolaterally over several 
segments (Fig 50-3) The lumbar and tho 
racic portions may be considered together as 
the longissimus thoracis et lumborum. This 
large mass of muscle begins at the iliac crest 
and continues craniad to the sixth cervical 
transverse process The surface of the lum 
bar portion is especially aponeurotic l'rom 
the eleventh to the seventh nbs a portion de 
taches from the medial surface to ctmrse 
craniad as the spinalis The fibers in general, 
anse from the spinous processes and course 
ventrolateraliy to insen in a serrated fashion 
on the accessory and transverse processes 
and the ribs The longissimus cervicis con 
tinues craniad to insert as four serrations on 
to the transverse processes of the third to 
sixth cervical vertebrae The longissimus 
capitis anses medial to the cranial cervical 
portion, from the first few thoracic transverse 
processes and from the last few cervical ar 
ticular processes It runs craniad lateral to 
the scmispinalis caplus to attach with the 
splenius on the mastoid portion of the tem 
poral bone (Fig. 50-2) There may be deeper 
fibers which end on the atlas The spinalis, 
after detaching from the medial side of the 



50-CARNIVOUE MYOLOGY 


15X7 


longissimus in the thoracic region (7 to 11), 
runs cramad to insert next to the muscle of 
the other side on the spinous processes of 
the last six ceivical vertebrae Between them 
is the nuchal ligament The muscle may be 
considered as having cervical and thoracic 
portions 

The transvcrsospinalis is a system of deep 
epaxial muscles Included is the semispinahs, 
detectable as the semispinahs capitis, which 
is a continuation cranially of cervical and 
thoracic portions It anses in the area of sep 
aration of the longtssimus and spinalis from 
the first few thoracic transverse processes 
In the neck it divides into the lm enter cervi- 
cis and complexus (Fig 50-2) The latter is 
more lateral and has continuous origins from 
the cervical articular processes between the 
attachments of the longissimus capitis and 
the multifidi The fibers run cramad to a tendi 
nous attachment on the dorsal nuchal line 
The medial muscle, biventer cervicis ad 
heres to the median raphe of the neck and 
runs from the cranial thoracic transverse 
processes to a roughened area ventrolateral 
to the external occipital protuberance It con 
tains several oblique tendinous inscriptions 
The multifidi consist of lumbar, thoracic and 
cervical portions which he on the sides of the 
vertebral spines (Fig 50-6) The thoracic and 
lumbar portions consist of numerous bundles 
which arise on the transverse articular and 
mamillary processes and course cramodor 
sally to attach to the caudal edge of the spine 
of at least the second vertebra cramad In 
the cervical region the separations are not 
so distinct The muscle mass lies over the 
cervical articular processes as far cramad 
as the axis It is lateral to the insertion of the 
spinalis The rotatores consist of long and 
short bundles which he deep to the multifidi 
in the cranial three quarters of the thorax 
(Fig 50 6) They are arranged like the mul 
tifidi but are more vertical and run between 
adjacent vertebrae only The transverso 
spinalis muscles are extensors of the verte- 


bral column They also fix the vertebral col 
umn, and of course the rotatores, acting uni 
laterally, tend to rotate the thoracic verte 
bral column about the longitudinal axis They 
are supplied by the dorsal spinal nerves 

The mlerspmalcs consist of horizontal 
fibers attaching to contiguous spinous proc- 
esses in the lumbar, thoracic and caudal 
cervical regions (Fig 50-6) They fix the 
vertebral column and are supplied by dorsal 
branches of the spinal nerves 

The intertransversani are located in all 
regions of the vertebral column Their bundles 
span two or more vertebrae Those of the Ium 
bar and thoracic regions are sparse fibers run 
ning ventrad and cramad from mamillary to 
accessory processes and between transverse 
processes as far as the fourth thoracic verte 
bra The cervical intertransversani are more 
prominent and consist of dorsal bundles run 
ning craniolaterally between articular and 
transverse processes and ventral groups of 
fibers coursing longitudinally along the trans 
verse processes (Fig 50-6) They fix the ver- 
tebral column or bend it laterally and are 
supplied by dorsal spinal nerves The caudal 
intertransversani are desenbed with the mus 
cles of the tail 

The thoracolumbar fascia is quite duck and 
stretches laterally over the epaxial muscles 
from the supraspinous ligament to give on 
gin to muscles and send deep intermuscular 
septa. In the lumbar region it attaches to the 
tips of the transverse processes and gives 
ongm to the abdominal muscles and the ser 
ratus dorsalis caudalis Fibers of the longis 
simus and lliocostalis anse from it deeply 
In the thoracic region a superficial sheet 
gives ongin to the latissimus dorsi The deep 
er portion passes medial to the scapula where 
it gives ongin to the splemus and semispinahs 
capitis A septum passes between the Jongis 
simus and the lliocostalis The lateral edge 
gives ongm to the serratus dorsalis cranialis 
Caudally it continues as the deep gluteal 
fascia 



FIGURE 50-6 Deep axial muscles of the don lateral view 


1 Rectus capitis dorsalis 2 otyiquus capitis cranialis 3 obliquus capitis caudalis 4 4 
5 iotigus colli 8 6 6 multifidi (cervicis thoracis lumborum) 7 interspinales 8 8 
tores cos tar um. 


4 intertransversani cervicis 5 
rotatores (long! breves) 9 leva 



1518 


CARNIVORE 


THORACIC MUSCIES 

The pectorales superficiales consist of crani 
al (descendens) and caudal (transversus) 
divisions m some species However, in the 
dog it is more convenient to desenbe a single 
muscle with separate slips (Fig 50-5) It 
arises on the midhne of the sternum next to 
the muscle of the other side as far caudally 
as the third segment The fiber bundles course 
laterally to dip deep to the cleidobrachialis 
and insert with that muscle and all along the 
crest of the humerus A portion seems to sepa 
rate from its surface 

The pectorahs profundus is broad at ns 
ongin from the ventral median raphe and 
the sternum from slightly caudal to the crani 
al extent of the pectorales superficiales to the 
fascia o\er the xiphoid area (Fig 50-5) The 
fibers course cramolaterally to bunch at a 
much less expansive insertion on the minor 
tuberosity of the humerus A fibrous portion 
passes over the biceps brachb to the major 
tuberosity The more caudal fibers insert by 
a fascia more distally on the humerus The 
cranial portion and the insertion are covered 
by the pectorales superficiales A superficial 
lateral portion tends to be somewhat sepa 
rated from the mam muscle The pectorals 
are adductors of the limb The pectoralis 
profundus pulls the trunk craniad on the ad 
vanced limb or retracts and extends the shoul 
der of the free limb The nerves come from 
the brachial plexus 

The serratus ventrahs consists of two por 
tions the serratus ventrahs cervicis and ser- 
ratus centralis thoracis (Fig 50-3) The en 
lire ronsrJr is fan shaped, arising fre m» ihe 
transverse processes of the last five cervical 
vertebrae and the middle portion of the first 
seven or eight nbs The muscle bundles con 
verge to insert on the facies serrata of the 
scapula Ventral to the ongin are the scaleni 
The last few costal attachments interdigi 
tate by a serrated edge with the ongin of the 
obliquus extemus abdominis The cervical 
and thoracic portions form a continuous sheet 
of muscle The muscle acts as a sling for the 
body when the forelimbs are planted The 
ventral cervical nerves supply the cervical 
portion segmentaliy, the thoracic portion 
is supplied by the long thoracic nerve which 
runs horizontally on its lateral surface 

The leiatores costarum anse as somewhat 
spindle shaped muscles from the transverse 
processes of the first 12 thoracic vertebrae 
and run caudolaterally to insert, in each case 
on the cranial border of the nb next caudal 
(Fig 50-6) They run no farther laterally than 
the iliocostalis Continuing laterally are the 
intercostales exterm, they pull the nbs cram- 
ad in inspiration. 

The intercostales externi occupy the inter 


costal spaces from the levatores costarum to 
approximately the costochondral junctions 
However, with each successive segment 
going caudally the muscles fill more inter- 
chondral space The fibers run caudo\ cntraliy 
from the caudal border of the cranial nb to 
the cranial borderof the caudal nb(Figs 50-8 
and 0) The ongin is thus on the cranial nb 
and the action is to pull the ribs craniad on 
inspiration 

The intercostales intemi fill the intercostal 
and interchondral spaces throughout their 
length The fiber direction is craniovcntral 
The ongin is thus from the caudal nb and the 
action is to retract the ribs In expiration Act- 
ing together the intercostals are inspiratory 
Several muscle bundles at the vertebral ends 
of the intercostales intemi may extend across 
one or more nbs, especially ribs 9 to 11 These 
are named the subcostales. 

The retractor costae is a thin triangular 
muscle, deep to the transversus abdominis, 
which bridges the space between the first 
few lumbar transverse processes and the 
last nb (Fig 50-7) It arises from the tho- 
racolumhar fascia 

The transversus thoracis lies on the inner 
surface of the sternum and sternal costal car- 
tilages except the first The fibers arise on the 
sternum as segmental bundles which course 
craniolaterally to insert on the costal carti 
lages It aids in expiration 
The rectus thoracis is a flat, almost rectan 
gular muscle (Fig 50-3) running caudoven 
trally from the first nb where the scalenus 
medius attaches to insert by a fascia with 
that of the origin of the rectus abdominis at 
the distal end of nb 3 nr 4 it advances the 
nbs in inspiration 

The muscles associated with the ribs and 
intercostal spaces are supplied by intercostal 
nerves 

The diaphragm consists of a tendinous 
central sheet surrounded by radiating mus 
cle (Fig 50-7) The tendinous center is it»la 
tively small and is indented dorsally by the 
crura. Muscle fibers attach along the costal 
arch where they butt against those of the 
transversus abdominis They continue to 
anse along the dorsal surface of the xiphoid 
cartilage to become those of the opposite side 
All fibers of the costal and sternal portions 
are directed toward the tendinous center 
The lumbar portion consists of right and left 
crura each of which attaches by a long har 
row bifid tendon to the ventral longitudinal 
ligament of the lumbar vertebrae Between 
the crura a fibrous ring forms the aortic hiatus 
for the aorta, vena azygos and thoracic duct 
The right crus is ■the larger and runs craniad 
from its tendon on the third and fourth lumbar 
vertebrae to spread out in the tendinous center 
of the diaphragm Its medial portion passes 



50 -CARNIVORE MYOLOGY 


1519 



of do g, 

1 , Central tendon; 1', sternal part, 1% costal part and 1”, 
lumbar part of diaphragm; 2, psoas minor; 3, psoas major; 
4, quadratus lumborum; 5, transversus abdominis; 6, re- 
tractor costae; 7, subcostales; 8. lntercostales intern!; 9. 
Intercostale* extend; 10, foramen venae cavae; 11, eso- 
phageal hiatus: 12, aortic hiatus. 


somewhat to the left of the midline and sur- 
rounds the esophagus, forming the esophageal 
hiatus. The left crus, although it arises like the 
other one from the lumbar vertebrae, does 
not extend as far craniad on the diaphragm. 
Laterally the crura are separated from the 
costal portion by connective tissue which 
passes ventral to the psoas muscles to form 
a lumbocostal arch where the pleura and 
peritoneum with their fascias are thus back 
to back. The vena cava passes through the 
tendinous center slightly to the right of the 
midline at the foramen venae cavae. The 
diaphragm is strongly convex toward the tho- 
racic cavity. It contracts in inspiration. The 
phrenic nerve which arises from the fifth 
to seventh cervical nerves reaches it on each 
side through the mediastinum or caval fold. 


ABDOMINAL MUSCLES 

The four abdominal muscles on each side 
form the abdominal wall (Fig. 50-3). They 
are, by necessity, expansive and relatively 
thin. Two are oblique, one is transversely 
oriented and another runs longitudinally 
near the midline. Three of them arise later- 
ally and attach to the midline ventrally by 
forming aponeuroses. The straight longitu- 
dinal muscle fills the area on each side of the 
midline where the aponeuroses of the others 
lie. 

The obliquus extemus abdominis is the most 
superficial of the group. It arises as an ex- 
pansive sheet of muscle from the middle por- 
tions of the third to twelfth ribs by distinct 
serrations (Fig. 50-1). The first few interdigi- 
tate with those of the serratus ventralis thora- 
cis. The mu scleal so aris es al ong th e en tire 1 um - 
bar area from the thoracolumbar fascia at 
the lateral border of the epaxial muscles. The 
fiber direction is caudoventral (Fig. 50-8). 
The insertion is by an aponeurosis which be- 
gins at about the costochondral junction or 
the lateral border of the rectus abdominis, 
except near the pelvis where it is quite ex- 
tensive. Here it is thickened and at the cau- 
dal edge extends from the area of the iliac 
tuberosity to the pubis and the prepubic ten- 
don. This caudal thickened portion of the 
aponeurosis of the obliquus extemus abdom- 
inis has been called the inguinal ligament. 
The combined aponeuroses of the abdominal 
muscles of both sides of the body form a fi- 
brous union on the ventral midline from the 
xiphoid cartilage to the prepubic tendon 
called the linea alba. 

The obliquus internus abdominis lies deep 
to the extemus. The fibeT direction, in gen- 
eral, is cranio ventral, placing the direction 
of the two oblique muscles at right angles. 
The origin is from the thoracolumbar fascia 



1520 


CARNIVORE 


and from the area of the cranial iliac spine 
The cranial portion attaches along the costal 
arch The remaining portion attaches to an 
aponeurosis which becomes narrower to- 
ward the caudal extent of the muscle Thus, 
cramally the fibers do not reach the lateral 
border of the rectus abdominis, but overbp 
it caudally The broad cranial aponeurosis 
also sends a portion deep to the rectus abdom 
inis The last muscle fibers tend to curve cau 
dally as they near their aponeurosis They only 
reach the cranial border of the deep inguinal 
nng, which they form The aponeurosis then 
sweeps caudally with that of the obllquus 
extemus abdominis superficial to the rectus 
abdominis A band of muscle splits from the 


last muscle fibers of the obliquus internus 
abdominis to constitute the cremaster, which 
attaches to the parietal byer of the vaginal 
tunic with its spermatic fascb In the male 
after tmvebng through the inguinal canal- 
The transversus abdominis is the deepest 
of the group and lies just outside the trans- 
verse fascia- The origin is along the mcdbl 
side of the costal arch as far cranbd as the 
xiphoid cartilage and the transversus tho- 
racis This portion arises with the costal part 
of the dbphragm, but the fibers of the two 
muscles run in the opposite direction toward 
their insertions The musculophrenic vessels 
course between their origins In the lumbar 
region the transversus abdominis arises from 



FIGURE 50-8 Suportcl moodo. of tnjok of 8c,; <poo,„„,„ p ro f„„d„, 

(From Miller ettL. 1964) 



50-carnivore myology 


1521 



FIGURE 90-9. Muscles of ol dog; deep dissection; ventral aspect, 
(p'rom Miller et al , 1964 ) 


the thoracolumbar fascia. The fibers P ass 
transversely to attach to an apone urosis 
which passes deep to the rectus abdtf 11111 ^ 5 
to join the linea alba. The last fibers the 
transversus abdominis do not go quite as ^ 
caudally as those of the obliquus interims a b- 
damisjis.. fe. feci., \asfc. few vajiscl^-bun- 
dies, as they approach the lateral bo* aer °* 
the rectus abdominis, pass superficial to that 
muscle to attach with the fibers of tl» e obli- 
quus intemus abdominis to the e* terna l 
sheath of the rectus abdominis (Fig. 50-9). 
Deeply, at this point, there is no apon euros i s 
of the transversus abdominis. Regula^Y the 
transversus muscle bundles join tfr e apo- 
neurosis slightly medial to the lateral border 
of the rectus abdominis. 

The rectus abdominis lies longitildhu^ly 


as the third muscle of the group between the 
external and interna, aponeurotic sheathes. 
The right and left muscles are separated only 
by the connective tissue of the linea alba (Fig. 
50-8). However, through a transveise plane 
with the last ribs, the linea alba is widened 
hv the. tpranxma. of the. umbilical, scar.. Tbn. 
muscle is broadest craniaily. It arises by a 
broad, flat tendon over the sternal costal carti- 
lages It inserts on the prepubic tendon (Fig. 
50-9) which attaches to the cranial border of 
the pubis between the iliopubic eminences. 
Three to six transverse tendinous Intersec- 
tions are spaced throughout the length of the 
muscle. 

The inguinal canal (Fig. 50-9) is directed 
craniolateraLI y from the superficial to the 
deep inguinal ring. The superficial ring is an 



CARNIVORE 


1522 


oval opening in the aponeurosis of the obliquus 
externus abdominis a short distance cranial to 
the pubis and medial to the lateral border of 
the rectus abdominis The contents of the 
canal going from external to internal, pass he 
tween the external oblique aponeurosis and 
the lateral border of the rectus, which is cov 
ered by the caudal turning last fibers and apo 
neurosis of the obliquus intcmus abdominis 
Lateral and cranial to that they pass caudal to 
the last muscle fibers of the obliquus intern us 
abdominis, which form the cranial border of 
the deep nng The caudal border of the deep 
nng is formed by the caudal continuing apo 
neurosis of the obliquus externus abdominis 
(Inguinal ligament) The last fibers of the 
transversus are really somewhat cranial to the 
deep inguinal nng The spermatic cord with 
the vaginal tunic and cremaster muscle in the 
male and the vaginal process in the female tra 
verse the cranial portion of the canal The ex 
temal pudendal vessels are in the caudal por 
tion of the canal Laterally and caudally the 
canal really has no limiting structures The 
cranial commissure of the superficial inguinal 
nng is weaker than the caudal commissure 
The transverse fascia lies outside the pen 
toneum the way the endothoracic fascia lies 
outside the pleura However, at the lateral 
edge of the psoas group it becomes contin 
uous with the iliac fascia, and at the pelvic 
inlet with the peh ic fascia. The deep external 
fascia covenng the abdominal wall does not 
form an elastic sheath in the dog 
The abdominal muscles contract to Increase 
intra abdominal pressure in defecation mic 
tuntjon expiration and partuntion They also 
flex the vertebral column They are supplied 
segmentally by the ventral branches of the 
spinal nerves which appear on the surface 
of the transversus abdominis 
The quadratus lumborum lies ventral to 
the last three thoracic vertebrae, the last two 
nbs and the lumbar vertebrae The fibers run 
longitudinally to attach to the transverse 
processes of the lumbar vertebrae and the 
ilium The muscle is covered ventrally by the 
psoas muscles However, its lateral portion 
is exposed ventral to the origin of the trans 
versus abdominis (Fig 50-7) The action is to 
fix the lumbar v ertebral column It is supplied 
by the ventral branches of the lumbar nerves 


MUSCLES OF THE TAIL 

(Musculi caudae) 

The caudal vertebrae are enclosed in mus 
cle The muscles begin on the lumbar and 
sacral vertebrae and continue caudally in a 
dorsal, lateral or ventral position They are 
supplied by the appropriate spinal nerves 


The sacrocaudalis (coccygeus) dorsalis lat- 
eralis attaches to the lumbar mamillary proc 
esses and lies between the multifidi and 
the longissimus More caudally it attaches to 
the sacral articular processes and the caudal 
vertebrae in the form of long bundles A num 
ber of long tendons replace the more super 
ficial layers on the caudal vertebrae The 
sacrocaudalis dorsalis mediahs consists of 
short segments which appear to be a con 
tmuanon of the multifidi at the beginning 
of the sacrum Individual segments course 
caudolaterally over several vertebrae The 
more superficial parts are somewhat tendi 
nous The sacrocaudalis \ entrails lateralis 
begins on the last lumbar vertebra It con 
tinues caudally as numerous long parts which 
anse along the ventral surfaces of the sa 
crum and caudal vertebrae The more cranial 
parts form long tendons and the more caudal 
parts shorter tendons which continue cau 
dally in the tail The sacrocaudalis ventrahs 
mediahs is shorter and more delicate and 
consists of individual bundles ansing and in 
serting over one or two vertebrae beginning 
on the caudal portion of the sacrum Small 
tendons are formed superficially which at 
tach to those of the lateral muscle Laterally 
between the sacrocaudalis dorsolateralis and 
ventrolateralis he the intertransversarn cau- 
dae (dorsalis and ventrahs) They consist of 
segments dorsal and ventral to the trans 
verse processes beginning at the caudal end 
of the sacrum The ventral muscle is the 
more delicate 

The muscles of the pelvic diaphragm in 
sert entirely or partially at the base of the 
tail The coccygeus originates on the ischiatic 
spine It courses dorsocaudally medial to the 
sacrotuberous ligament, fanning out some 
what to insert between the intertransversarn 
on the second to fifth caudal vertebrae The 
levator am originates on the pelvic floor and 
the shaft of the ilium It goes caudally medial 
to the caudal portion of the coccygeus to at 
tach to the sphincter am externus and insert 
by a strong tendon lateral and caudal to the 
rect ococcygeus on th e seven th caudal vertebra. 
The rectococcygeus consists of smooth mus 
cle fibers which continue caudally from the 
muscle of the rectal wall The nght and left 
portions fuse and insert in the midline on the 
fifth and sixth caudal vertebrae They tend 
to separate the insertions of the levator am 
The anal part of the retractor chtondls or 
penis consists of smooth muscle fibers which 
anse as a narrow band at the sacrocaudal 
junction just lateral to the rectococcygeus 
The fibers run caudo ventrally to insert on the 
sphincter am externus and continue as the 
retractor penis muscle in the male 

The muscles of the pelvic diaphragm de 
press the tail. When the tail is raised they 



50 - CARNIVORE MYOLOGY 


1523 


compress the rectum They are supplied by 
ventral branches of the last sacral spinal 
nerve The smooth muscles help to anchor the 
anus They are supplied by autonomic nerves 


MUSCLES OF THE THORACIC LIMB 

(Figs 50-10 and 11) 

The supraspinatus occupies the supra- 
spinous fossa of the scapula from which it 
takes origin (Fig 50-5) However, it more 
than fills the fossa and thus can be seen from 
a medial view cranial to the subscapulans 
The distal portion lies cranial to the shoulder 
joint and inserts by a strong tendon onto the 
cranial portion of the major tubercle of 
the humerus It is covered by the trapezius, 
omotransversanus and brachiocephalicus 
It extends the shoulder joint 
The infraspinatus lies in the infraspinous 
fossa. It arises from the fossa and the tendi 
nous sheet of the deltoideus The strong ten 
don of insertion crosses the caudal portion 
of the major tubercle of the humerus where 
the infraspinous bursa is located and inserts 
on a circular roughened area ventral to the 
cranial portion of the major tubercle It is 
covered, except proximally, by the deltoideus 
It acts mainly as a collateral ligament of the 
shoulder joint The supraspinatus and the 
infraspinatus are supplied by the suprascapu 
lar nerve 

The deltoideus consists of two portions 
which lie lateral to the scapula and caudal 
to the scapular spine (Fig 50-1) The larger 
portion (pars scapulans) arises along the 
scapular spine by means of an aponeurosis 
The smaller distal portion (pars acrovualis) 
arises from the acromion and partially over 
laps the proximal portion The two parts in 
sert together on the deltoid tuberosity of the 
humerus The deltoideus lies lateral to the 
infraspinatus and a part of the origins of the 
long and lateral heads of the triceps brachii 
The clavicular portion of the deltoideus of 
primates is represented as the clcidobrachialis 
in the dog 

Tiie teres minor is a small muscle which 
lies deep to the deltoideus, but caudal to the 
infraspinatus, at the shoulder joint It anscs 
from the caudal edge of the distal third of the 
scapula, crosses the flexor surface of the 
joint and inserts on the humerus slightly 
caudal and distal to the insertion of the infra 
spinatus 

The teres ms\Jor arises on the caudal angle 
of the scapula and courses dlstally medial 
to the teres minor and triceps brachii andcau 
dal to the suhscapularis to insert with the 
lulssimus dorsi on the teres tuberosity of the 
humerus It is rather flat and slender 



deitoSdeu* 5 5 . triceps brachii G bleep* brachii 7 
* “ nc ™ eui 9 9 • Rcxor «rr! ulnans 10 ex’ 
tensor carpi ulrairi, 11. extensor dlcMansm hleralis 12 

uSSr ™ mr rr J ‘ *2 *«*»*« radUll. 

14 braehSoradUll* 15 abductor digltit loneut 1G rrti-n 
wdltltl I r, dlfltil, |7 imrro.*.! 1 JSSSJaSS? 
1*1 extensor mliuculum. 



CARNIVORE 


1524 



' medial view. 

J, Subwapularij, 2. supraspinatui, 3, coracobrachialis; 
4, tere* major; 5. latUsimua dorxl. G, tensor fasciae an 
tcbTachii; 7, 7’, T, triceps brachii, 8, biceps brarhii. 9, 
brachial!* , 10. brachioradlalis. 11. extensor carpi ra- 
dial!*, 12, pronator teres, 13. flexor carpi radUlu, 14 , 14 '. 
flexor digltorum profundus; 15, flexor digitorum superfl- 
dalis. 16. flexor carpi ulnatis, 17, flexor retinaculum. 


The deltoideus, teres minor and teres major 
flex the shoulder joint. They are innervated by 
the axillary nerve. The latissimus dorsi, which 
is also a flexor of the shoulder joint, was de- 
scribed with the dorsal muscles. 

The subscapularis fills the subscapular 
fossa distal to the facies serrata. Tendinous 
bands divide the muscle longitudinally and 
converge at the insertion on the minor tu- 
bercle of the humerus. Its medial surface is 
flat. It acts mainly as a collateral ligament 
of the shoulder joint. The nerve supply is the 
subscapular and axillary nerves. 

The biceps brachii arises by a long but 
strong tendon from the supraglenoid tubercle. 
The tendon passes through the intertubercu- 
lar groove where an extension of the joint 
capsule acts as a bursa or tendon sheath for 
the tendon. Distal to the groove the tendon 
gives way to a fusiform muscle which de- 
scends craniomedial in the arm to insert by 
two tendons on the ulnar and radial tuber- 
osities, between which the brachialis inserts. 
The proximal portion of the muscle is 
sheathed in fibrous tissue. Deep tendinous 
strands and folds make the muscle fiber ar- 
rangement pennate. Distal tendinous ex- 
tensions join the antebrachial fascia. 

The brachialis occupies the sulcus m. brach- 
ialis. The distal portion becomes narrow, 
crosses the flexor surface of the elbow and 
passes deep to the biceps brachii to insert 
with the biceps on the radial tuberosity. It 
sends fibers between the tendons of insertion 
of the biceps to attach to the ulnar tuberosity. 
In the groove it is covered by the lateral por- 
tions of the triceps brachii (Fig. 50-5), Dis- 
tally it is medial to the dorsolateral antebrach- 
ial muscles. More proximally It is lateral to 
the insertions of the brachiocephalicus, pec- 
torales superficiales and deltoideus. 

The coracobrachialis is a short muscle 
which arises by a long, narrow tendon from 
the coracoid process of the scapula. The ten- 
don passes over the medial surface of the 
insertion of the subscapularis and is provided 
with a synovial tendon sheath. The muscle 
dips medial to the medial head of the triceps 
and the teres major to insert near them on 
the teres tubercle of the humerus. 

These cranial brachial muscles are sup- 
plied by the musculocutaneous nerve. The 
biceps brachii extends the shoulder joint and 
flexes the elbow joint; the brachialis flexes 
the elbow joint; the coracobrachialis adducts 
the humerus and extends the shoulder joint 
when it is partially extended. 

The triceps brachii consists of four heads 
which lie caudal to the shoulder joint and 
humerus and insert on the olecranon. The 
long head is the largest and arises from the 
caudal border of the scapula. As the fibers ap- 
proach the tendon of insertion, a caudal por- 



1525 


50 -CARNIVORE MYOLOGY 


ion is demarcated from the remainder of the 
ong head by a definite furrow. The combined 
tendon of insertion attaches to the caudal 
part of the olecranon. Between it and the 
olecranon is a bursa. The lateral head, which 
is next in size, arises by an aponeurosis from 
the lateral crest of the humerus. Its short, 
broad tendon of insertion blends with that of 
the long head. The medial head is small and 
spindle-shaped. It originates in the area of 
the teres tuberosity of the humerus between 
the coracobrachialis and the teres major. It 
inserts on the medial portion of the olecranon 
and joins the tendon of the long head. Be- 
tween the other heads and caudal to the hu- 
merus is the accessory head. It arises on the 
caudal part of the neck of the humerus and 
forms a long tendon which blends with the 
others on the olecranon 
The anconeus is short, but wide, and arises 
from the lateral epicondylar crest and lateral 
epicondyle of the humerus. It inserts along 
the lateral surface of the proximal end of the 
ulna. Its proximal portion lies deep to the tri- 
ceps brachii. 

The tensor fasciae antebrachii is a strap- 
like muscle which lies along the caudomedial 
surface of the long head of the triceps brachii. 
It inserts on the olecranon and also on the ante- 
brachial fascia. 

The caudal brachial muscles extend the 
elbow joint. The tensor fasciae antebrachii 
also flexes the shoulder joint and tenses the 
antebrachial fascia. The long head of the tri- 
ceps is a flexor of the shoulder joint also. They 
are supplied by the radial nerve. 

The caudal antebrachial muscles include 
the flexors of the carpus and digits They 
arise from the medial epicondyle of the hu- 
merus or adjacent areas of the radius and 
ulna. Among them are the pronators They 
are supplied by the median or ulnar nerves; 
the action of each-ds reflected in its name. 

The most medial muscle is the pronator 
teres, which arises from the medial epicon- 
dyle of the humerus and crosses the medial 
surface of the elbow joint to insert on the me- 
dial border of the radius proximal to its mid- 
dle. It is round in cross-section and is direc- 
ted distally and slightly cranially from origin 
to insertion. 

The flexor carpi radialis lies immediately 
caudal to the preceding muscle. Near the 
middle of the forearm it becomes a flat ten- 
don which continues distally through the 
palmar carpal ligament, where it Is invested 
in a synovial sheaJi, to divide and attach to 
the palmar sides of the proximal portions of 
metacarpals II and HI. 

The flexor dlgitorum supcrflcialis is next 
caudal in position and arises by a strong ten- 
don from the more caudal portion of the me- 
dial epicondyle of the humerus. It descends 


as a long fleshy muscle belly which becomes 
tendinous just proximal to the carpus. This 
strong tendon passes superficial to the flexor 
retinaculum medial to the accessory carpal 
bone. On the palmar surface of the proximal 
third of the metacarpus it splits into four ten- 
dons which follow the four main digits. Each 
forms a sleeve for the deep digital flexor ten- 
don at the level of the palmar sesamoids. Dis- 
tal to this point the superficial digital flexor 
tendon divides to pass on each side of the deep 
digital flexor tendon. It spreads out and inserts 
on the proximal end of the palmar surface of 
the middle phalanx while the deep digital 
flexor tendon continues (Fig. 50-12). 

The flexor carpi ulnaris is the most caudal 
muscle of the flexor group and consists of 
two portions. The smaller caudal portion, 
called the ulnar head, arises on the proxi- 
mal end of the ulna and descends lateral to 
the flexor digitorum superficialis to become 
a flat tendon at the forearm. It contacts the 



FIGURE 50-12. Muscles, tendons and ligaments 
of diffit of dog. 

1. Flexor dlgitorum superficial!*, 2. Jumbricalls; 3, 
flexor digitonim profundus. 4, interosseus, 5, extensor 
digltorum communis, 6, metacarpal bone II!. 7, palmar 
sesamoid bone, 8. dorsal sesamoid bones, 0, proximal 
phalanx. 10, middle phalanx. H, distal phalanx; ^collat- 
eral ligaments, 13, dorsal (elastic) ligament; 14, digital 
anuLor ligament*; 25, collateral sesamoid ligament. 



CARNIVORE 


1526 

remainder of the muscle but inserts inde 
pendently on the accessory carpal bone The 
larger humeral head anses by a short tendon 
on the medial epicondyle of the humerus 
lateral to the flexor digitorum superficialis 
It descends as a strong flat muscle deep to 
the latter to insert by a short tendon on the 
accessory carpal bone The ulnar head and 
the distal portion of the humeral head fuse 
with the antebrachial fascia. A bursa lies 
beneath the humeral origin of this muscle 
and the flexor digitorum superficialis An 
other bursa is located at the insertion on the 
accessory carpal bone 
The flexor digitorum profundusis thedeepest 
muscle of the caudal group It consists of three 
heads which unite proximal to the carpus 
to form a strong tendon which passes distally 
through the carpal canal In the metacarpal 
area it lies deep to the superficial digital flexor 
tendon The tendon gives a small medial por 
tion just distal to the carpus to the first digit 
and then divides for the four mam digits 
(Fig. 50-13) Each passes through the tu 
bular sheath {manica flexor id) formed by the 
flexor digitorum superficialis in the meta- 
carpophalangeal region to continue on the 
palmar surface of the digit and insert on the 
palmar tuberosity of the distal phalanx (Fig 
50-12) Each tendon of the flexor digitorum 
superficialis, as far as it exists, and that of 
the flexor digitorum profundus are bound 
down at the metacarpophalangeal joint, the 
more distal portion of the proximal phalanx 
and the proximal portion of the middle pha 
lanx by proximal, middle and distal anular 
ligaments The humeral head includes the 
major portion of the muscle and itself con 
sists of three bellies which anse by a common 
short tendon from the medial epicondyle of 
the humerus caudal to the origin of the flexor 
carpi radialis and deep to that of the flexor 
digitorum superficialis They lie caudal to the 
radius enclosed by the other muscles From 
the caudomedial portion of the radius, ex 
cept its distal portion, anses the small radial 
head Its tendon joins the main tendon at the 
proximal level of the carpus The ulnar head 
is next in size and originates along the caudal 
border of the ulna. It is deep to the flexor 
carpi ulnans and extensor carpi ulnans Its 
tendon joms the main tendon just proximal to 
the carpus 

Beneath the ongin of the flexor digitorum 
profundus is a bursa. Surrounding the tendon 
at the carpus is a synovial tendon sheath The 
tendons of both the flexor digitorum profun- 
dus and superficialis to the principal digits 
have common sheaths beginning at the sesa 
molds However, after the superficial digital 
flexor tendons split to insert, the sheaths 
continue along the deep digital flexor tendons 



FIGURE 50-13 Deep antebrachial and metacar- 
pal museles of dog, caudal and palmar new 

1 pronator quadratus 2 2 2* 2' flexor digitorum 
profundus 3 interflexorii 4 abductor dlgtti 1 brevis, 5 
flexor dlgitl I brevis 6 adductor dlgtti I 7 abductor digit 
V 8 flexor digit! V 9 lumbricale* 10 Interossel If pal 
mar anular ligament 12 flexor digitorum superficialis 


only The deep flexor tendon to the first digit is 
enclosed in a sheath for its entire length 
The pronator quadratus fills the space 
between the radius and ulna on the palmar 
surface Its fibers run distally and medially 
from the ulna to the radius 
The muscles of the flexor group which at- 
tach to the ulna are supplied by the ulnar 



50 -CARNIVORE MYOLOGY 


1527 


nerve Those that attach to the radius plus 
;he flexor digitorum superficialis and the 
pronator quadratus are supplied by the me 
dian nerve This arrangement also applies 
to the portions of the flexor digitorum pro 
fundus The action is as implied by the names 
The muscles that extend the carpus and 
digits lie cramolateral in the forearm and 
anse m general from the lateral epicondyle 
and lateral epicondylar crest of the humerus 
More distaily they are dorsal in the limb The 
abductor digiti I longus and the supinator 
are situated an this group They are all sup 
plied by the radial nerve 
Beginning cramolaterally and progressing 
caudally the first muscle is the brachioradi 
ahs, which is a long narrow muscle lying 
along the cephalic vein It is reduced m size 
to the extent that it may even be absent It 
arises from the lateral epicondylar crest and 
descends along the cranial portion of the ex 
tensor carpi radialls to insert on the pen 
osteum of the radius where the latter mus 
cle has become a tendon 
' The extensor carpi radiahs is the largest of 
the group and is next in position It anses 
from the lateral epicondylar ci est The muscle 
belly gives way to two tendons two thirds of 
the way distaily on the radius The two ten 
dons remain side by side surrounded by a 
synovial tendon sheath as they descend to 
the insertions They cross the middle sul 
cus of the radius and the extensor surface 
of the carpus to insert on the proximal part 
of metacarpal II (longus) and on metacarpal 
III (brevis) Near the origin the muscle is 
covered cramally by an aponeurotic sheath 
associated with the brachialis and biceps 
brachii 

The extensor digitorum communis lies cau 
dal to and partially deep to the extensor carpi 
radiahs and thus arises on the distal portion 
of the lateral epicondylar crest and the lateral 
epicondyle of the humerus The two muscles 
are joined at their origins by a common apo- 
neurosis The muscle belly becomes a tendon 
about two-thirds of the way down the radius, 
which consists of four parts packed together 
The tendon, enclosed in a synovial sheath, 
descends through the lateral sulcus of the 
radius and qver the extensor surface of the 
carpus Just distal to the carpus the tendon 
separates into four slender tendons, each of 
which continues to the dorsal surface of a 
main digit to insert on the extensor process 
of its distal phalanx. Deep to each tendon at 
the metacarpophalangeal and the proximal 
interphilangcal joint is a small sesamoid 
element. Each tendon receives the inter- 
osseous tendons at the proximal phalanx 
(Fig. 50-12) 

The extensor digitorum lateralis is next 
caudal in position, it Is shaped like the pre- 


ceding muscle but is slightly smaller Its on 
gin is not quite so proximal and is thus from 
the ulnar collateral ligament of the elbow and 
the lateral tuberosity of the radius There are 
two muscle bellies whose tendons he one 
upon the other The tendons are enclosed in 
a common sheath as they descend in the 
groove between the distal ends of the radius 
and ulna over 'the dorsolateral surface of the 
carpus to the metacarpus Here the tendons 
separate, in fact, the dorsomedial one divides 
into two tendons These join the common 
digital extensor tendons to digits III, IV and 
V and also insert on the proximal portions of 
the proximal and middle phalanges of those 
digits 

The extensor carpi ulnans is the most cau- 
dal muscle of the group It arises from the lat- 
eral epicondyle of the humerus Its strong 
broad tendon is in evidence soon after those 
of the other muscles of the group It passes 
over the lateral portion of the carpus without 
a groove and attaches to the proximal portion 
of metacarpal V At the carpus it is attached 
by fibrous tissue to the accessory carpal bone 

The supinator is a small muscle which 
anses from the lateral collateral ligament of 
the elbow joint by a short tendon and courses 
distaily and cramally for a short distance to 
insert along the dorsal surface of the proxi 
mal fourth of the radius It lies deep to the 
more cranial members of the extensor group 
and may dip deep to the pronator teres near 
its insertion 

The extensor digiti I (pollicis) et II is a very 
slender muscle which anses from the middle 
third of the dorsal surface of the ulna deep 
to the extensors It descends superficial to 
the ongin of the abductor between the long 
and lateral digital extensor tendons As its 
delicate tendon crosses the carpus it passes 
deep to the common digital extensor tendon 
to divide for the first two digits A very weak 
tendon may be dispatched to digit III The 
insertion in each case is with the common 
digital extensor tendon or on the bone at the 
distal end of the metacarpus 

The abductor digiti I (pollicis) longus arises 
from the lateral surface of the radius and 
ulna deep to the beginning of the tendons of 
the extensors and the interosseous mem 
branes Its fibers are directed obliquely me 
dially and distaily deep to the extensor digiti 1 
and II and the common digital extensor ten- 
don to cross superficial to the tendons of the 
extensor carpi radiahs It forms a tendon 
which passes through the media] sulcus of 
the radius and crosses the medial surface of 
the proximal portion of metacarpal I At this 
point a small sesamoid bone is buried in the 
tendon A bursa or small tendon sheath is 
associated with the tendon as it crosses the 
tendons of the extensor carpi ndiahs 



CARVIVORE 


1528 

The extensors of the digit extend both the 
carpus and the digits, those of the carpus ex 
tend only the carpus The supinator tends to 
supinate the paw, although such action is 
limited. The long abductor, of course, abducts 
the first digit It also extends it and causes 
medial deviation of the paw 
In addition to the tendons which insert in 
the paw there are a number of small special 
muscles which lie on the palmar surface 
The interflexorius is a slender round mus 
cle which lies on the palmar surface of the 
deep digital flexor tendon at the carpus (Fig 
50-13) At the middle of the metacarpus it 
forms small tendons which join those of the 
flexor digitorum superficiahs to digits II, III 
and IV The flexor digitorum brevis is a very 
small round muscle which lies in the meta 
carpus on the deep surface of the superficial 
digital flexor tendon to digit V Its relatively 
long tendon inserts on the transverse Uga 
ment of that metacarpophalangeal joint The 
lumbncales are three small muscles which 
he between the deep digital flexor tendons to 
the main digits (Fig 50-13) The small ten 
don of each muscle, in turn, inserts on the 
proximal medial surface of the proximal 
phalanx in digits III, IV and V (Fig. 50-12) 
These muscles flex the forepaw The inter 
flexonus is supplied by the median nerve, the 
flexor digitorum brevis and the lumbncales, 
by the ulnar nerve 

The deep muscles of the palmar side of the 
paw are supplied by the ulnar nerve They 
consist of abductors, flexors and adductors 
of the first and fifth digits (Fig. 50-13) and an 
adductor to the second digit Also palmar to 
each pnncipal digit is an interosseus muscle 
The interossei lie on the palmar side of the 
four main metacarpal bones (Fig 50-13) In 
each case the muscle arises from the palmar 
surface of the proximal end of the metacarpal 
bone The muscle of each mam digit divides 
as it approaches the distal end of the meta 
carpus and attaches by a tendon to each sesa 
mold bone A portion of each tendon con 
tinues over the collateral surfaces of the joint 
to unite with the common digital extensor 
tendon over the dorsal surface of the proximal 
phalanx (Fig 50-12) They flex the meta 
carpophalangeal joints 
Associated with the first digit are three very 
small muscles which are situated side by side 
on the palmar surface of metacarpal 1 From 
medial to lateral they are the abductor iigiti I 
(pollicis) brevis, flexor digiti I brevis and ad 
doctor digiti I (Fig. 50-13) They anse from 
the palmar carpal bgament and insert on the 
sesamoid bone or on the proximal phalanx. 
Since they are so close together they mainly 
flex digit I 


The three special muscles of digit V are the 
abductor digiti V, flexor digiti V and adductor 
digiti V The abductor is strong and arises 
on the accessory carpal bone It inserts by a 
tendon in common with the flexor on the 
lateral sesamoid and on the proximal phalanx 
of the fifth digit (Fig 50-33) It abducts the 
fifth digit The flexor is next medial in posi 
tion but arises distal and medial to the abduc 
tor on the distal ligament of the accessory 
carpal bone It flexes the fifth digit The ad 
ductor lies between Interossei III and IV At 
its ongin from the palmar carpal ligament it 
passes between interossei IV and V to insert 
on the medial surface of the metacarpal and 
proximal phalanx of digit V It adducts the 
fifth digit 

The adductor digiti II arises on the palmar 
carpal ligament between interossei II and ad 
ductor digiti V and passes between interossei 
II and III to insert by a tendon on the proxi 
mal phalanx of digit II 

The deep fascia sends intermuscular septa 
especially to the areas of bony ndges and 
prominences One of these is located at the 
insertion of the brachiocephalicus, biceps 
brachii and brachialjs The antebrachial mus 
cles are enclosed in a thick tube of fascia, 
which sends septa to the bones between the 
extensor and flexor groups The pads are 
firmly attached to the fascia. The flexor ret- 
inaculum (palmar carpal transverse bgament) 
is especially thick and bridges the flexor ten- 
dons to form the carpal canal The tendons are 
bound down on the dorsal surface of the car 
pus by the extensor retinaculum 


MUSCLES OF THE PELVIC LIMB 

(Figs 50-14 and 15) 

The pelvic limb includes the os coxae The 
sublumbar muscles insert on the os coxae 
and femur The iliopsoas consists of the psoas 
major and iliacus, which unite to insert on 
the trochanter minor of the femur The psoas 
major is narrow at its ongin from the trans 
verse processes of lumbar vertebrae 2 and 3 
It also attaches to lumbar vertebrae 4 to 7 It 
is ventral to the quadratus lumborum and 
lateral to the psoas minor As it continues cau 
dally it becomes thicker and wider and is 
reinforced by muscle fibers from the ventral 
surface of the ilium which constitute the 
iliacus The Uiopsoas flexes the hip joint and 
the vertebral column and laterally rotates the 
limb The psoas minor lies ventral to the quad 
ratus lumborum and is wide at its ongin, 
which is farther craniad than that of the psoas 



50 -CARNIVORE MYOLOGY 


1529 


EGURE 50-14 Deep muscles of pelvic limb of 
dog lateral view 

1 Sacrocaudalis dorsalis medialis 2 sacrocaudalis dor 
ills lateralis 3 intertransversani caudae 4 coccygeus 
. sacrocaudahs ventralis lateralis 6 levator am 7 i sacro- 
beral Ugament 8 piriformis 9 gluteus superficiales 
*eep part) 10 gluteus profundus 11 sartonus 12 12 
uadriceps femoris 13 gemelb 14 obturatorius in 
mus 15 quadratus femorus 16 adductor 17 semi 
embranosus 18 abductor cruris caudalis 19 semiten 
linosus 20 gastrocnemius 21 fibularis longus 22 
lblalis cranialis 23 flexor digitorum superficlalis 24 
lexor digitorum profundus 25 extensor digitorum 
ongus 26 fibularis brevis 27 extensor digitorum la 
.eralis 28 extensor digitorum brevis 29 extensor retina 
;ula. 




FKJUUF 50-15 I*i Lie limb of dog medial muscle*. 


1 Lcvuoranl 2 xacrocaudaii* ventralis medUlis 3 iwcroeaudali* 
\emral» UteniUs 4 tluteux medius 5 piriformii G coccygeu* 7 
obiumtortut Intermit 8 llloptous 9 |»to« minor 10 lO 1 II garturius 

II 11 qvudrkrp* femom 12 pectineu* 13 adductor 14 *eml 
membra no it i» 15 *r»clln IG temltrndinotui 17 tartrocoermus 
18 ttcant dlcitorum *ui>erf>cl-ili» 19 common calcaneal tendon 20 
2 O' 20* flexor ditUorum profundu* 21 poplitcu* 22 tlbivli* cran 
UtU 23 extentor digitorum longm 24 extender retinacula. 


1530 


CARNIVORE 


major It arises dorsal to the diaphragm as 
far craniad as the last thoracic vertebra and 
as it gams origin from the lumbar vertebrae 
the muscle belly becomes narrower and far 
ther from the midline This flat shiny tendon 
passes medial to the psoas major to insert on 
the tubercle of the arcuate line on the shaft of 
the ilium and proximal to the tubercle along 
the line for a short distance It acts as a flexor 
of the vertebral column These sublumbar 
muscles are supplied by the ventral branches 
of the lumbar nerves 

The muscles of the rump lie over the cau 
dal and lateral part of the pelvic wall and ex 
tend to the thigh The tensor fasciae latae is 
a triangular muscle (Fig 50-1) which arises 
from the coxal tuber and spreads out lateral 
to the quadriceps femons to join at the level 
of the greater trochanter the fascia lata The 
latter continues distally lateral to the quadn 
ceps to the patella The muscle tends to be 
divided longitudinally into two parts es 
pecially towards its insertion The action is to 
tense the fascia lata and thus flex the hip 
joint Its attachment by means of fascia to the 
patella makes it an extensor of the stifle also 
The gluteus superficialis is the most caudal 
of the gluteal group (Fig 50-1) It is rela 
tively small flat and rectangular in outline 
It lies caudal and partial!) superficial to the 
gluteus medius The origin is from the sa 
crum and first caudal vertebra and the proxi 
mal part of the sacrotuberous ligament the 
insertion is on the trochanter tertius There is 
usually a deep slip which is separate from the 
main portion of the muscle The muscle is 
covered by a heavy gluteal fascia from which 
it takes origin also 

The gluteus medius the largest of the glu 
teal muscles (Fig 50 1) anses from the en 
tire gluteal surface of the ilium Some fibers 
arise from the gluteal fascia. The fibers con 
verge to insert on the trochanter major of the 
femur (Fig 50-16) It is coiered caudally by 
the gluteus superficialis 

The gluteus profundus is completely cov 
ered by the gluteus medius and piriformis 
It arises along the lateral border of the shaft 
of the ilium from the wing to the ischiatic 
spine The fibers converge over the hip joint 
to insert craniil and distal to the gluteus 
medius on the trochanter major (Fig 50 16) 

The piriformis arises from the lateral bor 
der of the sacrum and the dorsal end of the 
sacrotuberous ligament in the region of the 
major ischiatic notch It lies deep to and in 
serts with the caudal portion of the gluteus 
medius It has a plump belly and a small but 
definite tendon of insertion. 

The gluteal muscles including the pin 
formis are extensors of the hip joint but also 
tend to be abductors of the limb The gluteus 
superficialis is supplied by the caudal gluteal 



dog 

1 Cluteus medius 2 gluteus profundus 3 articular!* 
coxae 4 adductor longus 5 5 obturatorius extemu* 6 
quadratus femorls 7 iliopsoas 


nerve The other gluteal muscles piriformis 
and tensor fasciae latae are supplied by the 
cranial gluteal nerve 

A group of short muscles which he caudal 
to the hip joint and are lateral rotators of the 
limb include the obturatorius mtemus 
gemelli and quadratus femons They are sup- 
bed by the ischiatic nerve The obturatorius 
interims anses from the inner surface of the 
pelvic floor It has a broad origin from the 
pubis and ischium medial to the obturator 
foramen which it covers as the fibers con 
verge to form a long strong flat tendon- The 
tendon is formed as the muscle fibers pass 
laterally over the minor ischiatic notch The 
tendon courses superficial to the gemelli 
to insert in the trochanteric fossa of the 
femur Under the tendon at the lateral border 
of the ischium is a synovial bursa. The gemelli 
anse from the lateral border of the ischium 
caudal to the gluteus profundus The two 
parts lie side by side demarcated only by the 
tendon of the obturatorius intemus with 
which they insert into the trochanteric fossa. 
The short but fleshy quadratus femons anses 
media] to the ischiatic tuber and courses 
cranially and distally proximal to the adductor 
to insert just distal to the trochanteric fossa. 

The caudal muscles of the thigh (hamstnng 
muscles) arise from the ischiatic tuber and 
descend to insert media! and lateral to the 
popliteal fossa. They extend the hip joint and 



50 -CARNIVORE MYOLOGY 


1531 


ixex the stifle joint when the limb is not sup- 
porting weight. When weight is supported 
hey extend the hip, stifle and tarsus (by 
means of association with the common cal- 
caneal tendon). The group is supplied by the 
Ischia tic nerve. The proximal and cranial 
portion of the lateral muscle which arises 
proximal to the ischiatic tuber from the sacjro- 
tuberous ligament is supplied by the caudal 
gluteal nerve. 

The biceps femoris is not only the largest 
and most lateral of the caudal muscles of the 
thigh but extends.into the buttock and leg 
(Fig. 50-1), It arises from the ischiatic tuber 
and the distal third of the sacrotuberous liga- 
ment The muscle spreads out distally and in- 
serts by a heavy fascial sheet which unites 
vith the fascia lata cranially, the crural fas- 
cia along the tibia and the common calcaneal 
;endon caudally. A small, deep but caudal por- 
tion may be separated longitudinally from the 
main mass of muscle. This portion arises 
from the ischiatic tuber by a definite tendon. 
The insertion of the biceps femoris is lateral 
to the deeper muscles of thigh, stifle and leg. 

The abductor cruris caudalis is a long, nar- 
row band which lies deep to the caudal por- 
tion of the biceps. It arises from the distal 
portion of the sacrotuberous ligament and 
inserts on the crural fascia with the most cau- 
dal fibers of the biceps femoris. It is covered 
by the biceps except at the popliteal level, 
where it becomes visible caudally. In addition 
to its function as part of the caudal muscles 
of the thigh, it tends to abduct the limb, as do 
the caudal fibers of the biceps. 

The semitendinosus is relatively slender 
because of its length but forms the caudal 
contour of the thigh. It arises from the ischi- 
atic tuber caudal to the origin of the biceps 
femoris and descends caudal to the biceps 
to swing medially and pass medial to the 
popliteal fossa and the caudal muscles of the 
leg. It inserts by means of a strong flat tendon 
onto the distal portion of the cranial border 
of the tibia distal to that of the gracilis. From 
these two muscles a .tendinous extension 
joins the common calcaneal tendon. The 
middle portion of the muscle tends to be 
concave caudally and contains a tendinous 
inscription. The proximal part of the muscle 
maybe seen from the lateral view. 

The semimembranosus is quite fleshy, and 
whereas it arises from the ischiatic tuber 
caudal and medial to the semitendinosus, it 
becomes cranial to the semitendinosus as it 
turns me